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A210936 Sum of prime factors of prime(n)-1 (counted with multiplicity). 3
0, 2, 4, 5, 7, 7, 8, 8, 13, 11, 10, 10, 11, 12, 25, 17, 31, 12, 16, 14, 12, 18, 43, 17, 13, 14, 22, 55, 13, 15, 15, 20, 23, 28, 41, 15, 20, 14, 85, 47, 91, 15, 26, 15, 18, 19, 17, 42, 115, 26, 35, 26, 16, 17, 16, 133, 71, 16, 30, 18, 52, 77, 25, 38, 22, 83 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

From an idea of Michael B. Porter.

LINKS

Paolo P. Lava, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A001414(A006093(n)). - Michel Marcus, Oct 05 2013

EXAMPLE

prime(10) = 29, and 29-1 = 28 = 2*2*7, so a(10) = 2+2+7 = 11.

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][1]*a[k][2], k=1..nops(a)));

od; end:

CROSSREFS

Cf. A023508, A023514, A210934

Sequence in context: A025511 A224367 A288758 * A140203 A085888 A187325

Adjacent sequences:  A210933 A210934 A210935 * A210937 A210938 A210939

KEYWORD

nonn

AUTHOR

Paolo P. Lava, Mar 30 2012

STATUS

approved

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Last modified January 22 08:43 EST 2018. Contains 298042 sequences.