|
|
A083137
|
|
Smallest palindromic number relatively prime to all the previous terms.
|
|
3
|
|
|
1, 2, 3, 5, 7, 11, 101, 131, 151, 181, 191, 313, 323, 353, 373, 383, 727, 757, 767, 787, 797, 919, 929, 989, 10001, 10301, 10501, 10601, 11111, 11311, 11411, 12421, 12721, 12821, 13031, 13331, 13831, 13931, 14141, 14341, 14741, 14941, 15151, 15451
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
323 is the first composite entry. Conjecture: sequence is infinite.
|
|
LINKS
|
|
|
MAPLE
|
isA002113 := proc(n)
if digrev(n) = n then
true;
else
false;
end if;
end proc:
option remember;
if n =1 then
1;
else
for p from procname(n-1)+1 do
if isA002113(p) then
rpr := true;
for i from 1 to n-1 do
if igcd(procname(i), p) > 1 then
rpr := false;
break;
end if;
end do:
if rpr then
return p ;
end if;
end if;
end do:
end if;
|
|
MATHEMATICA
|
a[1] = 1; a[n_] := a[n] = For[k = a[n-1]+1, True, k++, If[PalindromeQ[k] && AllTrue[Array[a, n-1], CoprimeQ[#, k]&], Return[k]]]; Array[a, 50] (* Jean-François Alcover, Jan 17 2018 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
base,nonn
|
|
AUTHOR
|
Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Apr 24 2003
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|