A244990 - OEIS

%I #11 Jul 23 2014 10:21:17

%S 1,3,6,7,9,12,13,14,18,19,21,24,26,27,28,29,35,36,37,38,39,42,43,48,

%T 49,52,53,54,56,57,58,61,63,65,70,71,72,74,76,78,79,81,84,86,87,89,91,

%U 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

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

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

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

%H Antti Karttunen, <a href="/A244990/b244990.txt">Table of n, a(n) for n = 1..10001</a>

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

%o (Scheme, with _Antti Karttunen_'s IntSeq-library)

%o (define A244990 (MATCHING-POS 1 1 (COMPOSE even? A061395)))

%Y Complement: A244991.

%Y Cf. A006530, A028260, A031215, A061395, A122111, A244988, A244321, A244322.

%K nonn

%O 1,2

%A _Antti Karttunen_, Jul 21 2014