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A005084 Sum of cubes of primes = 3 mod 4 dividing n. 6
0, 0, 27, 0, 0, 27, 343, 0, 27, 0, 1331, 27, 0, 343, 27, 0, 0, 27, 6859, 0, 370, 1331, 12167, 27, 0, 0, 27, 343, 0, 27, 29791, 0, 1358, 0, 343, 27, 0, 6859, 27, 0, 0, 370, 79507, 1331, 27, 12167, 103823, 27, 343, 0, 27, 0, 0, 27, 1331, 343, 6886, 0, 205379, 27, 0, 29791, 370, 0, 0, 1358, 300763, 0, 12194, 343, 357911 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

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

FORMULA

Additive with a(p^e) = p^3 if p = 3 (mod 4), 0 otherwise.

a(n) = A005064(n) - A005080(n) - 8*A059841(n). - Antti Karttunen, Jul 11 2017

MATHEMATICA

Array[DivisorSum[#, #^3 &, And[PrimeQ@ #, Mod[#, 4] == 3] &] &, 71] (* Michael De Vlieger, Jul 11 2017 *)

PROG

(Scheme) (define (A005084 n) (if (= 1 n) 0 (+ (if (= 3 (modulo (A020639 n) 4)) (A000578 (A020639 n)) 0) (A005084 (A028234 n))))) ;;  Antti Karttunen, Jul 11 2017

(PARI) a(n) = my(f=factor(n)); sum(k=1, #f~, if (((p=f[k, 1])%4) == 3, p^3)); \\ Michel Marcus, Jul 11 2017

CROSSREFS

Cf. A000578, A005064, A005080, A005082, A005083, A005085, A059841.

Sequence in context: A034246 A145336 A271246 * A050454 A277042 A224118

Adjacent sequences:  A005081 A005082 A005083 * A005085 A005086 A005087

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Antti Karttunen, Jul 11 2017

STATUS

approved

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Last modified September 23 17:54 EDT 2021. Contains 347618 sequences. (Running on oeis4.)