A025412 Numbers that are the sum of 4 distinct positive cubes in 2 or more ways.

1036, 1134, 1352, 1367, 1430, 1465, 1484, 1521, 1547, 1582, 1638, 1709, 1736, 1764, 1800, 1801, 1820, 1862, 1863, 1881, 1918, 1953, 1972, 2009, 2070, 2080, 2099, 2136, 2197, 2249, 2268, 2288, 2305, 2331, 2340, 2366, 2422, 2457, 2464, 2483, 2485, 2520

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

M:= 4000: # for terms <= M
V:= Vector(M):
for a from 1 while 4*a^3 < M do
  for b from a+1 while a^3 + 3*b^3 < M do
    for c from b+1 while a^3 + b^3 + 2*c^3 < M do
      for d from c+1 do
        v:= a^3 + b^3 + c^3 + d^3;
        if v > M then break fi;
        V[v]:= V[v]+1
od od od od:
select(t -> V[t] > 1, [$1..M]); # Robert Israel, Oct 23 2023

Crossrefs

Cf. A025409, A025421.

Sequence in context: A219445 A373407 A163558 * A025409 A043388 A184210

Adjacent sequences: A025409 A025410 A025411 * A025413 A025414 A025415

Keyword

nonn

Author

David W. Wilson

Status

approved