cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A348892 Number of solutions to +-1^3 +- 2^3 +- 3^3 +- ... +- n^3 = n.

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%I A348892 #12 Jan 28 2022 20:22:50
%S A348892 1,1,0,0,0,0,0,0,0,1,0,0,1,0,0,0,2,4,0,0,83,69,0,0,353,414,0,0,7800,
%T A348892 12496,0,0,48162,56870,0,0,733392,1253467,0,0,4892337,10022277,0,0,
%U A348892 45859303,149422926,0,0,623257759,1339056922,0,0,7453502893,13446831198
%N A348892 Number of solutions to +-1^3 +- 2^3 +- 3^3 +- ... +- n^3 = n.
%F A348892 a(n) = [x^n] Product_{k=1..n} (x^(k^3) + 1/x^(k^3)).
%o A348892 (Python)
%o A348892 from functools import lru_cache
%o A348892 @lru_cache(maxsize=None)
%o A348892 def b(n, i):
%o A348892     if n > (i*(i+1)//2)**2: return 0
%o A348892     if i == 0: return 1
%o A348892     return b(n+i**3, i-1) + b(abs(n-i**3), i-1)
%o A348892 def a(n): return b(n, n)
%o A348892 print([a(n) for n in range(54)]) # _Michael S. Branicky_, Jan 28 2022
%Y A348892 Cf. A063890, A158118, A348165.
%K A348892 nonn
%O A348892 0,17
%A A348892 _Ilya Gutkovskiy_, Jan 28 2022