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A293903 Sum of proper divisors of form 4k+3. 3
0, 0, 0, 0, 0, 3, 0, 0, 3, 0, 0, 3, 0, 7, 3, 0, 0, 3, 0, 0, 10, 11, 0, 3, 0, 0, 3, 7, 0, 18, 0, 0, 14, 0, 7, 3, 0, 19, 3, 0, 0, 10, 0, 11, 18, 23, 0, 3, 7, 0, 3, 0, 0, 30, 11, 7, 22, 0, 0, 18, 0, 31, 10, 0, 0, 14, 0, 0, 26, 42, 0, 3, 0, 0, 18, 19, 18, 42, 0, 0, 30, 0, 0, 10, 0, 43, 3, 11, 0, 18, 7, 23, 34, 47, 19, 3, 0, 7, 14, 0, 0, 54, 0, 0, 60 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..16384

Index entries for sequences related to sums of divisors

FORMULA

a(n) = Sum_{d|n, d<n} [3 == d mod 4]*d.

a(n) = A091570(n) - A293901(n).

MATHEMATICA

Array[DivisorSum[#, # &, Mod[#, 4] == 3 &] - Boole[Mod[#, 4] == 3] # &, 105] (* Michael De Vlieger, Oct 23 2017 *)

PROG

(PARI) A293903(n) = sumdiv(n, d, (d<n)*(3==(d%4))*d);

CROSSREFS

Cf. A050452, A091570, A293513, A293901.

Sequence in context: A292255 A095104 A021337 * A284444 A033685 A272974

Adjacent sequences:  A293900 A293901 A293902 * A293904 A293905 A293906

KEYWORD

nonn

AUTHOR

Antti Karttunen, Oct 19 2017

STATUS

approved

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Last modified May 21 01:01 EDT 2019. Contains 323429 sequences. (Running on oeis4.)