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A074376 s(3s-1)/2 where s is the sum of the prime factors of n (with repetition). 1
0, 5, 12, 22, 35, 35, 70, 51, 51, 70, 176, 70, 247, 117, 92, 92, 425, 92, 532, 117, 145, 247, 782, 117, 145, 330, 117, 176, 1247, 145, 1426, 145, 287, 532, 210, 145, 2035, 651, 376, 176, 2501, 210, 2752, 330, 176, 925, 3290, 176, 287, 210, 590, 425, 4187 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Neville Holmes, Integer Sequence Combinations [Broken link?]

EXAMPLE

a(20) = 9(3*9-1)/2 = 117 because 9 = 2+2+5 and 20 = 2*2*5.

MATHEMATICA

spf[n_]:=Module[{t=Total[Flatten[Table[#[[1]], #[[2]]]&/@FactorInteger[ n]]]}, (t(3t-1))/2]; Join[{0}, Array[spf, 60, 2]] (* Harvey P. Dale, Sep 23 2016 *)

PROG

(PARI) sopfr(n) = my(f=factor(n)); sum(k=1, matsize(f)[1], f[k, 1]*f[k, 2])

fn(n) = my(s=sopfr(n)); s*(3*s-1)/2 \\ Michel Marcus, Jul 11 2013

CROSSREFS

Applies A000326 to A001414. Cf. A074373, A074374, A074375.

Sequence in context: A242338 A217649 A131976 * A293502 A134340 A000326

Adjacent sequences:  A074373 A074374 A074375 * A074377 A074378 A074379

KEYWORD

easy,nonn

AUTHOR

W. Neville Holmes, Aug 29 2002

STATUS

approved

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Last modified September 17 19:16 EDT 2019. Contains 327137 sequences. (Running on oeis4.)