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A023508 Sum of exponents in prime-power factorization of n-th prime - 1. 3
0, 1, 2, 2, 2, 3, 4, 3, 2, 3, 3, 4, 4, 3, 2, 3, 2, 4, 3, 3, 5, 3, 2, 4, 6, 4, 3, 2, 5, 5, 4, 3, 4, 3, 3, 4, 4, 5, 2, 3, 2, 5, 3, 7, 4, 4, 4, 3, 2, 4, 4, 3, 6, 4, 8, 2, 3, 5, 4, 5, 3, 3, 4, 3, 5, 3, 4, 6, 2, 4, 6, 2, 3, 4, 5, 2, 3, 5, 6, 5, 3, 5, 3, 7, 3, 3, 7, 5, 4, 4, 2, 2, 6, 4, 3, 2, 3, 5, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..99.

MAPLE

with(numtheory);

P:=proc(i)

local a, k, n;

for n from 1 to i do

  a:=ifactors(ithprime(n)-1)[2]; print(add(a[k][2], k=1..nops(a)));

od; end: # Paolo P. Lava, Mar 30 2012

MATHEMATICA

Array[Plus@@Last/@FactorInteger[Prime[ # ]-1]&, 6! ] (* Vladimir Joseph Stephan Orlovsky, Feb 28 2010 *)

CROSSREFS

Cf. A210936

Sequence in context: A238279 A052275 A244798 * A151553 A151714 A039644

Adjacent sequences:  A023505 A023506 A023507 * A023509 A023510 A023511

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified December 19 01:34 EST 2014. Contains 252175 sequences.