A274758 Least number whose square is the sum of two positive triangular numbers in exactly n ways.

2, 4, 9, 34, 91, 66, 534, 121, 134, 716, 40391, 516

Offset: 1

Author

Altug Alkan, Jul 04 2016

Keywords

• nonn
• more

Comments

a(13) > 4*10^7, if it exists. - Giovanni Resta, Jul 04 2016

Examples

			a(1) = 2 because 2^2 = 1 + 3.
a(2) = 4 because 4^2 = 1 + 15 = 6 + 10.
a(3) = 9 because 9^2 = 3 + 78 = 15 + 66 = 36 + 45.
		

Crossrefs

Cf. A000217, A000290, A052346.

Extensions

a(9)-a(12) from Giovanni Resta, Jul 04 2016