A374714 Number of distinct sums i^3 + j^3 + k^3 + l^3 for 1<=i<=j<=k<=l<=n.

1, 5, 15, 35, 70, 119, 202, 317, 473, 671, 902, 1138, 1515, 2008, 2521, 3039, 3758, 4592, 5539, 6657, 7879, 9209, 10797, 12304, 14243, 16371, 18348, 21006, 23816, 26563, 29848, 33046, 36698, 40190, 44885, 49068, 54040, 59479, 64762, 70420, 76810, 83414, 90659, 98158, 105838, 114127, 123048

Offset

1,2

Links

Table of n, a(n) for n=1..47.

Prog

(PARI) a(n) = my(v=vector(4*n^3)); for(i=1, n, for(j=i, n, for(k=j, n, for(l=k, n, v[i^3+j^3+k^3+l^3]+=1)))); sum(i=1, #v, v[i]>0);
(Python)
def A374714(n): return len({i**3+j**3+k**3+l**3 for i in range(1, 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. A061791, A374713.

Cf. A374711, A374716.

Sequence in context: A374711 A015622 A346761 * A341134 A292103 A373463

Adjacent sequences: A374711 A374712 A374713 * A374715 A374716 A374717

Keyword

nonn

Author

Seiichi Manyama, Jul 17 2024

Status

approved