A235030 - OEIS

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A235030

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

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, 209, 211, 218, 228, 236, 237, 239, 241, 247, 266, 267, 271, 274, 278, 281, 285, 293, 295, 298, 304, 309, 311, 314, 316, 317, 323, 327, 342

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

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

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, ...

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.

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

LINKS

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

PROG

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

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

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

CROSSREFS

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

Sequence in context: A196185 A040342 A164009 * A048844 A008601 A033900

Adjacent sequences: A235027 A235028 A235029 * A235031 A235032 A235033

KEYWORD

nonn,base

AUTHOR

Antti Karttunen, Jan 02 2014

STATUS

approved