|
|
A080182
|
|
a(1) = 1, a(n+1) = a(n) + gpf(Sum_{i=1..n} a(i)), where gpf=A006530 (greatest prime factor).
|
|
3
|
|
|
1, 2, 5, 7, 12, 15, 22, 24, 35, 76, 275, 354, 377, 618, 2441, 2482, 5855, 18456, 20845, 46796, 47605, 53966, 54705, 182192, 182355, 211856, 213153, 214712, 216985, 1693212, 1694413, 1713714, 1716967, 1717074, 11728681, 11729202, 11738033, 11752860, 12041999, 12180558
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
LINKS
|
|
|
FORMULA
|
a(n+1) = a(n) + gpf(A080183(n)) for n > 0.
|
|
MATHEMATICA
|
gpf[n_] := FactorInteger[n][[-1, 1]];
a[n_] := a[n] = If[n == 1, 1, a[n-1] + gpf[Sum[a[i], {i, 1, n-1}]]];
|
|
PROG
|
b(n)={if(n==1, 1, my(f=factor(n)[, 1]); f[#f])}
seq(n)={my(a=vector(n), s=1); a[1] = 1; for(n=2, n, a[n] = a[n-1] + b(s); s += a[n]); a} \\ Andrew Howroyd, Apr 20 2021
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|