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A250289 Numbers n such that the numerator of Bernoulli(n) (A027641(n)) is a semiprime. 0
20, 24, 26, 34, 38, 40, 64, 72, 74, 114, 118, 144, 192 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..13.

Hisanori Mishima, Factorizations of many number sequences

Hisanori Mishima, Factorizations of many number sequences

Factorization of Bernoulli and Euler numbers

EXAMPLE

a(1) = 20 so the numerator of Bernoulli(20) = 174611 = 283 * 617 is a semiprime.

CROSSREFS

Cf. A092132.

Sequence in context: A117737 A062908 A111323 * A114843 A174629 A221651

Adjacent sequences:  A250286 A250287 A250288 * A250290 A250291 A250292

KEYWORD

nonn

AUTHOR

Eric Chen, Dec 24 2014

STATUS

approved

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Last modified September 22 20:23 EDT 2020. Contains 337291 sequences. (Running on oeis4.)