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A108608 5-almost primes whose sum of factors is a prime. 3
48, 80, 108, 176, 252, 300, 368, 405, 420, 464, 468, 500, 567, 660, 675, 684, 848, 891, 944, 980, 1020, 1116, 1136, 1140, 1323, 1332, 1377, 1424, 1428, 1452, 1539, 1548, 1575, 1616, 1700, 1716, 1740, 1820, 1860, 1875, 1932, 2096, 2156, 2196, 2295, 2300 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

EXAMPLE

48=2*2*2*2*3 (5-almost prime) and 2+2+2+2+3=11 is a prime.

PROG

(PARI) is(n)=my(f=factor(n)); sum(i=1, #f~, f[i, 2])==5 && isprime(sum(i=1, #f~, f[i, 1]*f[i, 2])) \\ Charles R Greathouse IV, Oct 11 2013

CROSSREFS

Cf. A107707, A108607, A108609 (resp.) 3, 4, 6 (resp.)-almost primes whose sum of factors is a prime.

Sequence in context: A260363 A261553 A110229 * A030628 A178739 A261548

Adjacent sequences:  A108605 A108606 A108607 * A108609 A108610 A108611

KEYWORD

nonn

AUTHOR

Zak Seidov, Jun 12 2005

STATUS

approved

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Last modified October 21 22:47 EDT 2019. Contains 328315 sequences. (Running on oeis4.)