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A357239
Inverse Moebius transform of tetranacci number (A000078).
1
0, 0, 1, 1, 2, 5, 8, 16, 30, 58, 108, 214, 401, 781, 1493, 2888, 5536, 10705, 20569, 39707, 76433, 147420, 283953, 547566, 1055028, 2034029, 3919974, 7556717, 14564533, 28075593, 54114452, 104311848, 201062094, 387564973, 747044844, 1439986130, 2775641472, 5350241528, 10312882883
OFFSET
1,5
FORMULA
G.f.: Sum_{k>=1} x^(3*k) / (1 - x^k - x^(2*k) - x^(3*k) - x^(4*k)).
G.f.: Sum_{k>=1} A000078(k) * x^k / (1 - x^k).
a(n) = Sum_{d|n} A000078(d).
MATHEMATICA
nmax = 39; CoefficientList[Series[Sum[x^(3 k)/(1 - x^k - x^(2 k) - x^(3 k) - x^(4 k)), {k, 1, nmax}], {x, 0, nmax}], x] // Rest
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Sep 19 2022
STATUS
approved