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A244991 Numbers whose greatest prime factor is a prime with an odd index; n such that A006530(n) is in A031368. 9
2, 4, 5, 8, 10, 11, 15, 16, 17, 20, 22, 23, 25, 30, 31, 32, 33, 34, 40, 41, 44, 45, 46, 47, 50, 51, 55, 59, 60, 62, 64, 66, 67, 68, 69, 73, 75, 77, 80, 82, 83, 85, 88, 90, 92, 93, 94, 97, 99, 100, 102, 103, 109, 110, 115, 118, 119, 120, 121, 123, 124, 125, 127, 128 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Equally, numbers n for which A061395(n) is odd.

A122111 maps each one of these numbers to a unique term of A026424 and vice versa.

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10001

FORMULA

For all n, A244989(a(n)) = n.

PROG

(Scheme, with Antti Karttunen's IntSeq-library)

(define A244991 (MATCHING-POS 1 1 (COMPOSE odd? A061395)))

CROSSREFS

Complement: A244990.

Cf. A006530, A026424, A031368, A061395, A122111, A244989, A244321, A244322.

Sequence in context: A289058 A102798 A247886 * A004612 A066208 A169743

Adjacent sequences:  A244988 A244989 A244990 * A244992 A244993 A244994

KEYWORD

nonn

AUTHOR

Antti Karttunen, Jul 21 2014

STATUS

approved

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Last modified January 15 19:17 EST 2019. Contains 319171 sequences. (Running on oeis4.)