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A005079 Sum of squares of primes = 1 mod 4 dividing n. 7
0, 0, 0, 0, 25, 0, 0, 0, 0, 25, 0, 0, 169, 0, 25, 0, 289, 0, 0, 25, 0, 0, 0, 0, 25, 169, 0, 0, 841, 25, 0, 0, 0, 289, 25, 0, 1369, 0, 169, 25, 1681, 0, 0, 0, 25, 0, 0, 0, 0, 25, 289, 169, 2809, 0, 25, 0, 0, 841, 0, 25, 3721, 0, 0, 0, 194, 0, 0, 289, 0, 25, 0, 0, 5329, 1369, 25, 0, 0, 169, 0, 25, 0, 1681, 0, 0, 314 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

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

FORMULA

Additive with a(p^e) = p^2 if p = 1 (mod 4), 0 otherwise.

a(n) = A005063(n) - A005083(n) - 4*A059841(n). - Antti Karttunen, Jul 11 2017

MATHEMATICA

Array[DivisorSum[#, #^2 &, And[PrimeQ@ #, Mod[#, 4] == 1] &] &, 85] (* Michael De Vlieger, Jul 11 2017 *)

PROG

(Scheme) (define (A005079 n) (if (= 1 n) 0 (+ (if (= 1 (modulo (A020639 n) 4)) (A000290 (A020639 n)) 0) (A005079 (A028234 n))))) ;; Antti Karttunen, Jul 11 2017

(PARI) a(n) = my(f=factor(n)); sum(k=1, #f~, if (((p=f[k, 1])%4) == 1, p^2)); \\ Michel Marcus, Jul 11 2017

CROSSREFS

Cf. A000290, A005063, A005078, A005080, A005081, A005083, A059841.

Sequence in context: A067669 A068741 A255403 * A167624 A181614 A108321

Adjacent sequences:  A005076 A005077 A005078 * A005080 A005081 A005082

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Antti Karttunen, Jul 11 2017

STATUS

approved

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Last modified October 20 10:45 EDT 2019. Contains 328257 sequences. (Running on oeis4.)