

A134376


Numbers whose sum of prime factors (counted with multiplicity) is not prime.


26



1, 4, 8, 9, 14, 15, 16, 18, 20, 21, 24, 25, 26, 27, 30, 32, 33, 35, 36, 38, 39, 42, 44, 46, 49, 50, 51, 55, 57, 60, 62, 64, 65, 66, 68, 69, 70, 72, 74, 77, 78, 81, 84, 85, 86, 87, 91, 92, 93, 94, 95, 98, 100, 102, 105, 106, 110, 111, 112, 114, 115, 116, 119, 120, 121, 122
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OFFSET

1,2


COMMENTS

The first term is 1, since 1 has no prime factors and so the sum of prime factors evaluates to zero.
Conjecture: a(n) ~ n.  Charles R Greathouse IV, Apr 28 2015


LINKS

Hieronymus Fischer, Table of n, a(n) for n = 1..10000


EXAMPLE

a(2) = 4, since 4 = 2*2 and 2+2 = 4 is not prime.
a(5) = 14, since 14 = 2*7 and 2+7 = 9 is not prime.


PROG

(PARI) sopfr(n)=my(f=factor(n)); sum(i=1, #f~, f[i, 1]*f[i, 2])
is(n)=!isprime(sopfr(n)) \\ Charles R Greathouse IV, Apr 28 2015


CROSSREFS

Cf. A000040, A001222, A100118, A046363, A133620, A133621, A133880, A133890, A133900, A133910, A133911, A134330, A134331, A134332, A134333, A134334, A134344, A078177.
Sequence in context: A010429 A140282 A161757 * A163408 A060299 A120512
Adjacent sequences: A134373 A134374 A134375 * A134377 A134378 A134379


KEYWORD

nonn


AUTHOR

Hieronymus Fischer, Oct 23 2007


EXTENSIONS

Edited by the author at the suggestion of T. D. Noe, May 20 2013


STATUS

approved



