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A244990

After 1, numbers whose greatest prime factor is a prime with an even index; n such that A061395(n) is even.

1, 3, 6, 7, 9, 12, 13, 14, 18, 19, 21, 24, 26, 27, 28, 29, 35, 36, 37, 38, 39, 42, 43, 48, 49, 52, 53, 54, 56, 57, 58, 61, 63, 65, 70, 71, 72, 74, 76, 78, 79, 81, 84, 86, 87, 89, 91, 95, 96, 98, 101, 104, 105, 106, 107, 108, 111, 112, 113, 114, 116, 117, 122, 126, 129, 130, 131, 133, 139, 140, 142, 143, 144

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OFFSET

1,2

COMMENTS

Equally, after 1, natural numbers n such that A006530(n) is in A031215.

A122111 maps each one of these numbers to a unique term of A028260 and vice versa.

LINKS

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

FORMULA

For all n, A244988(a(n)) = n.

PROG

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