A053612 Numbers such that 1+2+3...+a(n) = 1+4+9+...+r^2, for some r.

1, 10, 13, 645

Offset: 1

Author

Jud McCranie, Mar 19 2000

Keywords

• fini
• full
• nonn

Examples

			1^2 + 2^2 + 3^2 + 4^2 + 5^2 = 1 + 2 + 3 + ... + 10, so 10 is in the sequence.
		

References

• Joe Roberts, Lure of the Integers, page 245 (entry for 645).

Links

• R. Finkelstein, H. London, On triangular numbers which are sums of consecutive squares, J. Number Theory 4 (1972), 455-462.

Crossrefs

Cf. A039596, A053611.