A035163 Composite numbers k, not a power of 2, such that the E(k) == 1 (mod k), where E(k) is the k-th Euler number (A000364).

15, 91, 289, 319, 435, 561, 692, 703, 1016, 1105, 1369, 1495, 1729, 1885, 1891, 2105, 2465, 2701, 2755, 2821, 3367, 4371, 5551, 6409, 6601, 7456, 8224, 8569, 8695, 8911, 9088, 10585, 10621, 11305, 11849, 12121, 12403, 13981, 14065, 15051, 15841, 16471, 17104

Offset

1,1

Links

Table of n, a(n) for n=1..43.

Mathematica

Select[Range[1000], CompositeQ[#] && #/2^IntegerExponent[#, 2] > 1 && Divisible[Abs[EulerE[2*#]] - 1, #] &] (* Amiram Eldar, Nov 26 2020 *)

Prog

(PARI) a000364(n)=subst(bernpol(2*n+1), 'x, 1/4)*4^(2*n+1)*(-1)^(n+1)/(2*n+1);
lista(nn) = {forcomposite(n=1, nn, if ( n != 2^valuation(n, 2), if (Mod(a000364(n), n) == 1, print1(n, ", ")); ); ); } \\ Michel Marcus, Apr 18 2015

Crossrefs

Cf. A000364, A081730.

Sequence in context: A218408 A048630 A326148 * A237516 A020242 A020255

Adjacent sequences: A035160 A035161 A035162 * A035164 A035165 A035166

Keyword

nonn

Author

Benoit Cloitre, Apr 06 2003

Extensions

More terms from Hans Havermann, Apr 07 2003

a(23)-a(43) from Amiram Eldar, Nov 26 2020

Status

approved