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A107801
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a(1) = prime(1), for n >= 2, a(n) is the smallest prime not previously used which contains a digit from a(n-1).
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29
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2, 23, 3, 13, 11, 17, 7, 37, 31, 19, 29, 59, 5, 53, 43, 41, 47, 67, 61, 71, 73, 79, 89, 83, 103, 101, 107, 97, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277
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OFFSET
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1,1
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COMMENTS
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a(n) = prime(n) for almost all n. Probably a(n) = prime(n) for all n > N for some N, but N must be very large. If it exists, N > 10^1000. - Charles R Greathouse IV, Jul 19 2011
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LINKS
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FORMULA
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For n>=29, A(107800+i)(n) = A(107800+j)(n), 1 <= i < j <= 14. - Vladimir Shevelev, Mar 18 2012
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MATHEMATICA
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p=Prime[1]; b={p}; d=p; Do[Do[r=Prime[c]; If[FreeQ[b, r]&&Intersection@@IntegerDigits/@{d, r}=!={}, b=Append[b, r]; d=r; Break[]], {c, 1000}], {k, 60}]; b
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PROG
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(PARI) common(a, b)=a=vecsort(eval(Vec(Str(a))), , 8); b=vecsort(eval(Vec(Str(b))), , 8); #a+#b>#vecsort(concat(a, b), , 8)
in(v, x)=for(i=1, #v, if(v[i]==x, return(1))); 0
lista(nn) = {my(v=[2]); for(n=2, nn, forprime(p=2, default(primelimit), if(!in(v, p)&&common(v[#v], p), v=concat(v, p); break))); v; }
(Haskell)
import Data.List (intersect, delete)
a107801 n = a107801_list !! (n-1)
a107801_list = 2 : f 2 (tail a000040_list) where
f x ps = g ps where
g (q:qs) | null (show x `intersect` show q) = g qs
| otherwise = q : f q (delete q ps)
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CROSSREFS
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Other cases of seed: A107802 (a(1) = 3), A107803 (a(1) = 5), A107804 (a(1) = 7), A107805 (a(1) = 11), A107806 (a(1) = 13), A107807 (a(1) = 17), A107808 (a(1) = 19), A107809 (a(1) = 23), A107810 (a(1) = 29), A107811 (a(1) = 31), A107812 (a(1) = 37), A107813 (a(1) = 41), A107814 (a(1) = 43).
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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