A051140 a(n) = (A000110(n) - A000994(n+2))/2.

0, 0, 0, 0, 1, 8, 47, 259, 1437, 8208, 48659, 300553, 1937958, 13052028, 91784452, 673328720, 5146726651, 40934788112, 338292605257, 2900716040495, 25769979503573, 236876549095324, 2249873611378525, 22053647698650293, 222832106687369092

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn

Examples

			a(7) = (877 - 359)/2 = 259.
		

Crossrefs

Cf. A000110, A000994.