A181489 Composite Flavius' numbers (A000960) whose prime factors are again Flavius' numbers.

27, 39, 49, 63, 91, 133, 147, 399, 567, 763, 2187, 13239, 15379, 15883, 21207, 32761, 151599, 173563, 180739, 268423, 746607, 2277163, 2557359, 3114783, 8218083, 28604419, 65002743, 68944959, 91727883, 93742347, 237963999, 310488507

Offset

1,1

Comments

Contains A181488 as a subsequence.

Links

Klaus Brockhaus, Table of n, a(n) for n = 1..50

Index entries for sequences related to the Josephus Problem

Prog

(PARI) A181489(Nmax) = { my(S=[]); for(n=2, Nmax, my(F=n); for(i=1, n-1, F=(n-i)*ceil(F/(n-i)+1)); S=setunion(S, Set(F)); isprime(F) & next; for(i=1, #F=factor(F)~, setsearch(S, F[1, i])|next(2)); print1(factorback(F~), ", "))}

Crossrefs

Sequence in context: A365960 A097228 A039614 * A369251 A369252 A117103

Adjacent sequences: A181486 A181487 A181488 * A181490 A181491 A181492

Keyword

nonn

Author

M. F. Hasler, Oct 29 2010

Extensions

a(22)-a(32) from Donovan Johnson and Klaus Brockhaus, Oct 30 2010

Status

approved