A168047 Numbers k that divide the k-th isolated number.

1, 2, 3, 4, 12, 25, 30, 470, 1224, 57843, 145122, 16805481, 5285171382

Offset

1,2

Links

Table of n, a(n) for n=1..13.

Formula

{k: k | A167706(k)}.

Prog

(PARI) lista(pmax) = {my(p1 = 2, p2 = 3, c = 1); print1(c, ", "); forprime(p3 = 5, pmax, if(p2 == p1 + 2, c++; if(!((p1+1)%c), print1(c, ", "))); if(p2 != p1 + 2 && p2 != p3 - 2, c++); p1 = p2; p2 = p3); } \\ Amiram Eldar, May 17 2024

Crossrefs

Cf. A167706.

Sequence in context: A295754 A059810 A037397 * A236371 A333620 A173446

Adjacent sequences: A168044 A168045 A168046 * A168048 A168049 A168050

Keyword

nonn,more

Author

Juri-Stepan Gerasimov, Nov 17 2009

Extensions

Definition and a(6), a(7) corrected; 4 terms added - R. J. Mathar, Jun 04 2010

a(12)-a(13) from Amiram Eldar, May 17 2024

Status

approved