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A359290 Number of divisors of 4*n-2 of form 4*k+3. 3
0, 1, 0, 1, 1, 1, 0, 2, 0, 1, 2, 1, 0, 2, 0, 1, 2, 2, 0, 2, 0, 1, 2, 1, 1, 2, 0, 2, 2, 1, 0, 3, 0, 1, 2, 1, 0, 3, 2, 1, 2, 1, 0, 2, 0, 2, 2, 2, 0, 3, 0, 1, 4, 1, 0, 2, 0, 2, 2, 2, 1, 2, 0, 1, 2, 1, 2, 4, 0, 1, 2, 2, 0, 3, 0, 1, 2, 2, 0, 2, 2, 1, 4, 1, 0, 3, 0, 3, 2, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,8
LINKS
FORMULA
a(n) = A001842(4*n-2).
G.f.: Sum_{k>0} x^(2*k)/(1 - x^(4*k-1)).
G.f.: Sum_{k>0} x^(3*k-1)/(1 - x^(4*k-2)).
MATHEMATICA
Table[Count[Divisors[4 n-2], _?(IntegerQ[(#-3)/4]&)], {n, 100}] (* Harvey P. Dale, May 09 2023 *)
a[n_] := DivisorSum[4*n-2, 1 &, Mod[#, 4] == 3 &]; Array[a, 100] (* Amiram Eldar, Aug 16 2023 *)
PROG
(PARI) a(n) = sumdiv(4*n-2, d, d%4==3);
(PARI) my(N=100, x='x+O('x^N)); concat(0, Vec(sum(k=1, N, x^(2*k)/(1-x^(4*k-1)))))
(PARI) my(N=100, x='x+O('x^N)); concat(0, Vec(sum(k=1, N, x^(3*k-1)/(1-x^(4*k-2)))))
CROSSREFS
Sequence in context: A360764 A096800 A036586 * A092928 A321090 A219026
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Dec 24 2022
STATUS
approved

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Last modified July 18 03:55 EDT 2024. Contains 374377 sequences. (Running on oeis4.)