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.

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A175377 a(n) = A175376(n^2).

Original entry on oeis.org

1, 7, 27, 27, 33, 81, 117, 125, 125, 131, 251, 275, 275, 311, 335, 335, 349, 493, 493, 613, 613, 637, 637, 697, 697, 727, 871, 991, 999, 1023, 1143, 1143, 1191, 1191, 1215, 1215, 1281, 1449, 1569, 1617, 1737, 1785, 1785, 1809, 1889, 1985, 1985, 2033, 2033
Offset: 0

Views

Author

R. J. Mathar, Apr 24 2010

Keywords

Comments

Number of integer triples (x,y,z) satisfying x^4+y^4+z^4 <= n^2, -n <= x,y,z <= n.

Crossrefs

Programs

  • Maple
    N:= 100: # to get a(1)..a(N)
    A:= Array(0..N):
    for i from 0 while i^4 <= N^2 do
      if i=0 then ai:= 1 else ai:= 2 fi;
      for j from 0 while i^4 + j^4 <= N^2 do
        if j=0 then aj:= 1 else aj:= 2 fi;
        for k from 0 do
          v:= ceil((i^4 + j^4 + k^4)^(1/2));
          if v > N then break fi;
          if k = 0 then ak:= 1 else ak:= 2 fi;
          A[v..N]:= map(`+`,A[v..N] ,ai*aj*ak);
    od od od:
    convert(A,list); # Robert Israel, May 01 2019
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