A103651 The set N of numbers such that each positive integer can be written in the form p + n, where p is 0 or a prime and n in N, in an even number of ways.

0, 2, 3, 4, 5, 12, 15, 19, 21, 24, 26, 30, 31, 32, 33, 37, 38, 40, 42, 43, 44, 47, 48, 49, 50, 51, 52, 53, 54, 60, 61, 68, 69, 71, 73, 74, 78, 79, 80, 82, 84, 85, 87, 90, 94, 103, 107, 110, 111, 115, 117, 120, 124, 127, 136, 140, 141, 142, 143, 144, 145, 146, 147, 150, 156, 157

Offset

1,2

Links

Table of n, a(n) for n=1..66.

Formula

The terms are the exponents in the expansion of 1/S read mod 2 where S = 1 + Sum_{p prime} x^p.

Crossrefs

Cf. A108345, A132229.

Sequence in context: A132027 A306077 A329793 * A093713 A057472 A333390

Adjacent sequences: A103648 A103649 A103650 * A103652 A103653 A103654

Keyword

nonn

Author

Nadia Heninger and N. J. A. Sloane, Dec 16 2007

Status

approved