A259746 Triangular numbers representable as x*y+x+y such that x and y are triangular numbers, x>=y>1.

15, 120, 153, 351, 406, 741, 1891, 3081, 3403, 4465, 5151, 5565, 6555, 9453, 9591, 18721, 22791, 38226, 39903, 46056, 52326, 79401, 85491, 91378, 159895, 187578, 207690, 222111, 227475, 229503, 266815, 274911, 280875, 326028, 334971, 354903, 373680, 410871, 474825, 609960

Offset: 1

Author

Alex Ratushnyak, Jul 04 2015

Keywords

• nonn

Comments

A subsequence of A000217, A254671 and A259745.

Up to 10^12, only 3 terms admit two representations, namely 22791, 410871 and 1675365. - Giovanni Resta, Jul 19 2015

Examples

			153 = 6*21 + 6 + 21.
351 = 15*21 + 15 + 21.
406 = 10*36 + 10 + 36.
		

Links

• Giovanni Resta, Table of n, a(n) for n = 1..500

Crossrefs

Cf. A000217, A254671, A259745.