

A242423


Numbers in whose prime factorization the indices of primes do not sum to a triangular number.


4



3, 4, 7, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 20, 23, 24, 26, 31, 32, 33, 34, 35, 37, 38, 39, 41, 42, 43, 44, 45, 49, 50, 51, 52, 53, 54, 55, 56, 58, 59, 60, 61, 62, 63, 65, 66, 67, 68, 69, 70, 71, 72, 74, 75, 77, 78, 79, 80, 81, 82, 83, 84, 87, 88, 89, 90, 92, 93, 94, 95, 96, 97, 98, 99, 100
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OFFSET

1,1


COMMENTS

Numbers k such that A010054(A056239(k)) is zero, or equally, such that A002262(A056239(k)) is not zero.
These are numbers such that any iterations of A242424 started from them lead eventually to a cycle greater than one. Please see the comments and references at A242422.


LINKS

Antti Karttunen, Table of n, a(n) for n = 1..27575


EXAMPLE

3 = p_2 is present, because 2 is not a triangular number.
4 = p_1 * p_1 is present, because 1+1 = 2 is not a triangular number.


PROG

(Scheme, with Antti Karttunen's Intseqlibrary)
(define A242423 (ZEROPOS 1 1 (COMPOSE A010054 A056239)))


CROSSREFS

Complement: A242422.
Cf. A215366, A242424, A000217, A002262, A010054, A056239.
Sequence in context: A138225 A114889 A174659 * A010444 A010398 A010435
Adjacent sequences: A242420 A242421 A242422 * A242424 A242425 A242426


KEYWORD

nonn


AUTHOR

Antti Karttunen, May 16 2014


STATUS

approved



