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A005074 Sum of primes = 2 mod 3 dividing n. 8
0, 2, 0, 2, 5, 2, 0, 2, 0, 7, 11, 2, 0, 2, 5, 2, 17, 2, 0, 7, 0, 13, 23, 2, 5, 2, 0, 2, 29, 7, 0, 2, 11, 19, 5, 2, 0, 2, 0, 7, 41, 2, 0, 13, 5, 25, 47, 2, 0, 7, 17, 2, 53, 2, 16, 2, 0, 31, 59, 7, 0, 2, 0, 2, 5, 13, 0, 19, 23, 7, 71, 2, 0, 2, 5, 2, 11, 2, 0, 7, 0, 43, 83, 2, 22, 2, 29, 13, 89, 7, 0, 25, 0, 49, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10000

FORMULA

Additive with a(p^e) = p if p = 2 (mod 3), 0 otherwise.

a(n) = A008472(n) - A005070(n) - 3*A079978(n). - Antti Karttunen, Jul 10 2017

MATHEMATICA

Array[DivisorSum[#, # &, And[PrimeQ@ #, Mod[#, 3] == 2] &] &, 95] (* Michael De Vlieger, Jul 11 2017 *)

PROG

(Scheme) (define (A005074 n) (if (= 1 n) 0 (+ (if (= 2 (modulo (A020639 n) 3)) (A020639 n) 0) (A005074 (A028234 n))))) ;; Antti Karttunen, Jul 10 2017

(PARI) a(n) = my(f=factor(n)); sum(k=1, #f~, if (((p=f[k, 1])%3) == 2, p)); \\ Michel Marcus, Jul 11 2017

CROSSREFS

Cf. A005070, A005075, A005076, A005077, A005090, A008472, A079978.

Sequence in context: A209701 A158855 A344908 * A161564 A078182 A133394

Adjacent sequences:  A005071 A005072 A005073 * A005075 A005076 A005077

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Antti Karttunen, Jul 10 2017

STATUS

approved

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Last modified August 1 17:43 EDT 2021. Contains 346402 sequences. (Running on oeis4.)