A265845 Numbers that are sums of consecutive (positive) cubes in more than one way.

216, 8000, 33075, 64000, 89559, 105525, 164800, 188784, 189189, 216000, 343000, 353241, 443456, 608391, 1271600, 2370816, 3132116, 3132675, 3184236, 5821200, 5832000, 9018000, 9769375, 11437525, 20793591, 22153600, 24359616, 28685440, 35937000, 47651373

Offset: 1

Author

Reinhard Zumkeller, Dec 16 2015

Keywords

• nonn

Comments

A131643 (cubes that are also sums of three or more consecutive positive cubes) is a sparse subsequence: only 17 of its terms appear in the first 1000 terms of A265845. - Jonathan Sondow, Jan 10 2016

Examples

			a(1) = 216 = 6^3 = 3^3 + 4^3 + 5^3;
a(2) = 8000 = 20^3 = 11^3 + 12^3 + 13^3 + 14^3;
a(3) = 33075 = 11^3 + 12^3 + 13^3 + 14^3 + 15^3 + 16^3 + 17^3 + 18^3 + 19^3 = 15^3 + 16^3 + 17^3 + 18^3 + 19^3 + 20^3.
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

Crossrefs

Subsequence of A217843; subsequences: A000578, A005898, A027602, A027603, A062682.

Supersequence of A131643.

Programs

Haskell

import Data.Set (singleton, deleteFindMin, insert, Set)
a265845 n = a265845_list !! (n-1)
a265845_list = f (singleton (1, (1, 1))) 0 0 where
   f s z z' = if y == z && z' /= z then y : f s'' y z else f s'' y z
              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