A235030 - OEIS

%I #8 Jan 15 2014 13:42:40

%S 19,38,57,59,76,79,89,95,103,109,114,118,133,137,139,149,152,157,158,

%T 171,177,178,179,190,191,206,209,211,218,228,236,237,239,241,247,266,

%U 267,271,274,278,281,285,293,295,298,304,309,311,314,316,317,323,327,342

%N Numbers such that A235027(A235027(n)) <> n; Numbers which are divisible by any of the odd terms of A204219.

%C Sequence consists of all the primes in A204219 (after 2), together with all of their multiples.

%C Note that this is not the same as the numbers that do not occur in A235027 ("Garden of Eden" numbers for A235027), a subsequence of this sequence, which begins as: 19, 38, 57, 59, 76, 79, 89, 95, 103, 109, 114, 118, 133, 137, 139, 149, 152, 157, 158, 171, 177, 178, 179, 190, 191, 206, 211, 218, 228, 236, 237, 239, 241, 266, 267, 271, 274, 278, 281, 285, 293, 298, 304, 309, 311, 314, 316, 317, 327, 342, 347, 354, 356, 358, ...

%C The first term that occurs in this sequence, but not in the "GoE"-sequence is a(27)=209, as a(139) = 209 = 11*19 and 139 = A235146(2), the least integer which requires two steps to reach a fixed point or 2-cycle.

%C Both the above "GoE"-sequence, and its differences from this will be submitted later.

%H Antti Karttunen, <a href="/A235030/b235030.txt">Table of n, a(n) for n = 1..10001</a>

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

%o (define A235030 (MATCHING-POS 1 0 (lambda (n) (not (= (A235027 (A235027 n)) n)))))

%o (define A235030 (MATCHING-POS 1 2 (lambda (n) (any (lambda (x) (not (prime? x))) (map A056539 (ifactor n))))))

%Y Cf. A204219, A235027, A235145, A235146, A056539.

%K nonn,base

%O 1,1

%A _Antti Karttunen_, Jan 02 2014