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A064142 Sum of all distinct primes dividing central binomial coefficient C(n, floor(n/2)). 1
0, 2, 3, 5, 7, 7, 12, 14, 12, 12, 23, 23, 29, 29, 32, 34, 48, 48, 62, 62, 61, 61, 81, 81, 73, 73, 69, 69, 98, 98, 127, 129, 123, 123, 130, 130, 148, 148, 161, 161, 195, 195, 227, 227, 204, 204, 251, 251, 253, 253, 257, 257, 307, 307, 323, 323, 316, 316, 367, 367 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = A008472(A001405(n)).

MATHEMATICA

sop[n_] := If[n<2, 0, Total[First /@ FactorInteger[n]]]; Table[ sop[ Binomial[n, Floor[n/2]]], {n, 60}] (* Giovanni Resta, Jun 22 2018 *)

PROG

(PARI) sopf(n)= { my(f, s=0); f=factor(n); for(i=1, matsize(f)[1], s+=f[i, 1]); return(s) }

a(n)=sopf(binomial(n, n\2)); \\ Harry J. Smith, Sep 08 2009

CROSSREFS

Cf. A008472, A001405.

Sequence in context: A060308 A224911 A270176 * A067792 A119317 A198424

Adjacent sequences:  A064139 A064140 A064141 * A064143 A064144 A064145

KEYWORD

nonn

AUTHOR

Labos Elemer, Sep 11 2001

STATUS

approved

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Last modified December 8 00:04 EST 2021. Contains 349590 sequences. (Running on oeis4.)