A374711 Number of distinct sums i^3 + j^3 + k^3 + l^3 for 0<=i<=j<=k<=l<=n.

1, 5, 15, 35, 69, 123, 192, 297, 450, 636, 874, 1157, 1442, 1894, 2430, 3010, 3606, 4401, 5320, 6361, 7571, 8864, 10277, 11997, 13621, 15692, 17922, 20022, 22742, 25742, 28625, 32088, 35440, 39238, 42917, 47598, 51955, 57120, 62743, 68134, 73947, 80549, 87193, 94657, 102397, 110221, 118738, 127921, 135988

Offset

0,2

Links

Table of n, a(n) for n=0..48.

Prog

(PARI) a(n) = my(v=vector(4*n^3+1)); for(i=0, n, for(j=i, n, for(k=j, n, for(l=k, n, v[i^3+j^3+k^3+l^3+1]+=1)))); sum(i=1, #v, v[i]>0);
(Python)
def A374711(n): return len({i**3+j**3+k**3+l**3 for i in range(n+1) for j in range(i, n+1) for k in range(j, n+1) for l in range(k, n+1)}) # Chai Wah Wu, Jul 18 2024

Crossrefs

Cf. A374707, A374710.

Cf. A047801, A374714.

Sequence in context: A063382 A069983 A005894 * A015622 A346761 A374714

Adjacent sequences: A374708 A374709 A374710 * A374712 A374713 A374714

Keyword

nonn

Author

Seiichi Manyama, Jul 17 2024

Status

approved