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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).
2
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
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
Sequence in context: A218408 A048630 A326148 * A237516 A020242 A020255
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