A067778 - OEIS

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A067778

Numbers k such that gcd(k, numerator(B(2*k))) is not squarefree where B(2*k) are the Bernoulli numbers.

25, 49, 75, 98, 121, 125, 169, 175, 196, 225, 242, 245, 275, 289, 325, 338, 343, 361, 363, 375, 392, 425, 475, 484, 490, 507, 525, 529, 539, 575, 578, 625, 637, 675, 676, 686, 722, 725, 726, 775, 784, 825, 833, 841, 845, 847, 867, 875, 925, 931, 961, 968

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

All members so far are themselves not squarefree. - Robert G. Wilson v, Aug 28 2004

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[ Range[1000], !SquareFreeQ[ GCD[ #, Numerator[ BernoulliB[2# ]] ]] &] (* Robert G. Wilson v, Aug 28 2004 *)

CROSSREFS

Cf. A013929, A027641, A027642, A097704.

Sequence in context: A020196 A020294 A103214 * A350061 A067893 A067794