A060861 Least number of the form x^2 + y^3 (x, y nonnegative) in exactly n ways.

3, 0, 1, 225, 1025, 92025, 1334025, 5472225, 35964225, 930860225, 1000837225, 4979585600, 38515961025, 88154795025, 2046945411225, 88813460025, 5684061441600, 13052612865600, 64745012358225

Offset

0,1

Comments

A045634(a(n)) = n and A045634(m) <> n for m < a(n). [Reinhard Zumkeller, Jul 17 2010]

a(n) > 2*10^14 for n >= 19. [Donovan Johnson, Dec 13 2008]

a(19) <= 4143680790926400 = 64*a(18). [Jon E. Schoenfield, Aug 11 2010]

Links

Table of n, a(n) for n=0..18.

Example

a(3)=225: A045634(225) = #{15^2+0^3, 10^2+5^3, 3^2+6^3} = 3;
a(4)=1025: A045634(1025) = #{32^2+1^3, 31^2+4^3, 30^2+5^3, 5^2+10^3} = 4;
a(5)=92025: A045634(92025) = #{303^2+6^3, 255^2+30^3, 213^2+36^3, 152^2+41^3, 30^2+45^3} = 5.

Crossrefs

Sequence in context: A270880 A217580 A197858 * A067169 A257927 A011339

Adjacent sequences: A060858 A060859 A060860 * A060862 A060863 A060864

Keyword

nonn

Author

David W. Wilson, May 04 2001

Extensions

a(14) and a(16)-a(18) from Donovan Johnson, Dec 13 2008

a(0) and examples from Reinhard Zumkeller, Jul 17 2010

Status

approved