A271638 The total sum of the cubes of all parts of all compositions of n.
1, 10, 48, 170, 512, 1398, 3580, 8770, 20808, 48206, 109652, 245850, 544864, 1196134, 2605164, 5636210, 12124280, 25952382, 55312516, 117440650, 248512656, 524288150, 1103102108, 2315255970, 4848615592, 10133438638, 21139292340, 44023414970, 91536490688
Offset: 1
Examples
The two compositions of n=2 are 2 and 1+1. The total sum of the cubes is a(2) = 2^3+1^3+1^3 = 10.
Links
- Index entries for linear recurrences with constant coefficients, signature (6,-13,12,-4).
Crossrefs
Cf. A027992 (sum of squares).
Programs
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Mathematica
Table[(13 n - 36) 2^(n - 1) + 6 n + 18, {n, 29}] (* or *) Rest@ CoefficientList[Series[x (1 + 4 x + x^2)/((1 - 2 x) (1 - x))^2, {x, 0, 29}], x] (* Michael De Vlieger, Apr 11 2016 *)
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PARI
x='x+O('x^99); Vec(x*(1+4*x+x^2)/((2*x-1)*(1-x))^2) \\ Altug Alkan, Apr 11 2016
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Python
for n in range(1,50):print((13*n-36)*2**(n-1)+6*n+18) # Soumil Mandal, Apr 11 2016
Formula
G.f.: x*(1 + 4*x + x^2)/((1 - 2*x)*(1 - x))^2.
a(n) = (13*n - 36)*2^(n - 1) + 6*n + 18.