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A250296 Number n such that A057137(n) is a semiprime. 0
3, 4, 7, 11, 17, 27, 31, 124, 157, 247 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

First unknown: 397.

LINKS

Table of n, a(n) for n=1..10.

EXAMPLE

a(4) = 11 so A057137(11) = 12345678901 = 857 * 14405693 is a semiprime.

CROSSREFS

Cf. A120819, A057137, A046461.

Sequence in context: A069950 A147869 A319106 * A279785 A100581 A093090

Adjacent sequences:  A250293 A250294 A250295 * A250297 A250298 A250299

KEYWORD

nonn,base

AUTHOR

Eric Chen, Dec 25 2014

STATUS

approved

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Last modified November 15 04:00 EST 2018. Contains 317225 sequences. (Running on oeis4.)