OFFSET
1,1
COMMENTS
See A062682 for sums of two or more consecutive positive cubes in more than one way. - Reinhard Zumkeller, Dec 16 2015
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(1) = 1^3 + 2^3 = 9.
a(2) = 2^3 + 3^3 = 35.
a(3) = 1^3 + 2^3 + 3^3 = 36.
MAPLE
amin:= proc(b, N) local r;
r:= b^2*(b+1)^2 - 4*N; if r > 0 then iroot(r, 4) else 1 fi
end proc:
A265377:= proc(N) # to get all terms <= N
local a, b;
sort(convert(select(`<=`, {seq(seq(b^2*(b+1)^2/4 - a^2*(a-1)^2/4,
a = amin(b, N) .. b-1), b=2..1+iroot(floor(N/2), 3))}, N), list))
end proc:
A265377(10000);
MATHEMATICA
With[{nn=12}, Select[Sort[Flatten[Table[Total/@Partition[Range[nn]^3, n, 1], {n, 2, nn}]]], #<=((nn(nn+1))/2)^3&]] (* Harvey P. Dale, Dec 25 2015 *)
PROG
(Haskell)
import Data.Set (singleton, deleteFindMin, insert, Set)
a265377 n = a265377_list !! (n-1)
a265377_list = f (singleton (1 + 2^3, (1, 2))) (-1) where
f s z = if y /= z then y : f s'' y else f s'' y
where s'' = (insert (y', (i, j')) $
insert (y' - i ^ 3 , (i + 1, j')) s')
y' = y + j' ^ 3; j' = j + 1
((y, (i, j)), s') = deleteFindMin s
-- Reinhard Zumkeller, Dec 17 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert Israel, Dec 07 2015
STATUS
approved