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A005078 Sum of primes = 1 mod 4 dividing n. 6
0, 0, 0, 0, 5, 0, 0, 0, 0, 5, 0, 0, 13, 0, 5, 0, 17, 0, 0, 5, 0, 0, 0, 0, 5, 13, 0, 0, 29, 5, 0, 0, 0, 17, 5, 0, 37, 0, 13, 5, 41, 0, 0, 0, 5, 0, 0, 0, 0, 5, 17, 13, 53, 0, 5, 0, 0, 29, 0, 5, 61, 0, 0, 0, 18, 0, 0, 17, 0, 5, 0, 0, 73, 37, 5, 0, 0, 13, 0, 5, 0, 41, 0, 0, 22, 0, 29, 0, 89, 5, 13, 0, 0, 0, 5, 0, 97, 0, 0, 5, 101 (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 if p = 1 (mod 4), 0 otherwise.

a(n) = A008472(n) - A005082(n) - 2*A059841(n). - Antti Karttunen, Jul 11 2017

MATHEMATICA

Array[DivisorSum[#, # &, And[PrimeQ@ #, Mod[#, 4] == 1] &] &, 101] (* Michael De Vlieger, Jul 11 2017 *)

PROG

(PARI) a(n)=my(f=factor(n)[, 1]); sum(i=1, #f, if(f[i]%4==1, f[i])) \\ Charles R Greathouse IV, Mar 11 2014

(Scheme) (define (A005078 n) (if (= 1 n) 0 (+ (if (= 1 (modulo (A020639 n) 4)) (A020639 n) 0) (A005078 (A028234 n))))) ;; Antti Karttunen, Jul 11 2017

CROSSREFS

Cf. A005069, A005079, A005080, A005081, A005082, A008472, A059841.

Sequence in context: A048894 A047766 A324323 * A284446 A270030 A284104

Adjacent sequences:  A005075 A005076 A005077 * A005079 A005080 A005081

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Antti Karttunen, Jul 11 2017

STATUS

approved

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Last modified February 21 02:02 EST 2020. Contains 332086 sequences. (Running on oeis4.)