A092679 Numbers k such that 3*2^k has only one anti-divisor.

0, 1, 5, 17

Offset

1,3

Comments

Next term should be greater than 1000.

See A066272 for definition of anti-divisor.

Links

Table of n, a(n) for n=1..4.

Formula

A092680(n) = 3*2^a(n).

Prog

(Python)
A092679 = [i for i, n in enumerate(map(lambda x:3*2**x, range(20))) if len([d for d in range(2, n, 2) if n%d and not 2*n%d]+[d for d in range(3, n, 2) if n%d and 2*n%d in [d-1, 1]])==1] # Chai Wah Wu, Aug 09 2014

Crossrefs

Cf. A066466, A092680.

Sequence in context: A341436 A263906 A160739 * A277534 A090592 A340706

Adjacent sequences: A092676 A092677 A092678 * A092680 A092681 A092682

Keyword

nonn,hard,more

Author

Lior Manor, Mar 03 2004

Status

approved