A181488 Composite Flavius' numbers (A000960) whose divisors are again Flavius' numbers.

39, 49, 91, 133, 763, 15883, 21207, 32761, 180739, 268423, 746607, 2277163, 28604419, 93742347, 13192600483, 124387470307, 3898087261291, 13987912482103, 69089500671469

Offset

1,1

Comments

Sequence A118130 is the analog for lucky numbers A000959.

a(20) > A000960(10^7). - Donovan Johnson, Aug 23 2012

Links

Table of n, a(n) for n=1..19.

Index entries for sequences related to the Josephus Problem

Prog

(PARI) A181488(Nmax) = { my(S=[]); for(n=1, 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; fordiv(F, d, setsearch(S, d)||next(2)); print1(F", "))}

Crossrefs

Sequence in context: A235151 A050439 A199993 * A020305 A216978 A252719

Adjacent sequences: A181485 A181486 A181487 * A181489 A181490 A181491

Keyword

nonn

Author

M. F. Hasler, Oct 29 2010

Extensions

a(13)-a(16) from Donovan Johnson, Oct 30 2010

a(17)-a(18) from Donovan Johnson, Nov 11 2010

a(19) from Donovan Johnson, Aug 23 2012

Status

approved