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A081730 Numbers n such that the n-th Euler number == 1 (mod n). 3
1, 2, 3, 4, 5, 7, 8, 11, 13, 15, 16, 17, 19, 23, 29, 31, 32, 37, 41, 43, 47, 53, 59, 61, 64, 67, 71, 73, 79, 83, 89, 91, 97, 101, 103, 107, 109, 113, 127, 128, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..62.

FORMULA

All primes, all power of 2 are in the sequence. The composites are in A035163.

PROG

(PARI) a000364(n)=subst(bernpol(2*n+1), 'x, 1/4)*4^(2*n+1)*(-1)^(n+1)/(2*n+1);

lista(nn) = {for (n=1, nn, if (Mod(a000364(n), n) == 1, print1(n, ", ")); ); } \\ Michel Marcus, Apr 18 2015

CROSSREFS

Cf. A000364, A035163, A069042.

Sequence in context: A053868 A241912 A269870 * A162408 A162721 A176176

Adjacent sequences:  A081727 A081728 A081729 * A081731 A081732 A081733

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Apr 06 2003

EXTENSIONS

More terms from Weston Markham (weston.markham(AT)gmail.com), May 22 2005

STATUS

approved

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Last modified February 23 18:13 EST 2019. Contains 320437 sequences. (Running on oeis4.)