A115648 Square numbers which are the sum of distinct double factorials (A006882).

1, 4, 9, 16, 25, 49, 64, 121, 169, 400, 441, 961, 1444, 3844, 3969, 4225, 4356, 4900, 5184, 10404, 11449, 11881, 14400, 15625, 47089, 47524, 56644, 57600, 139129, 145924, 149769, 182329, 192721, 695556, 705600, 792100, 837225, 2073600

Offset: 1

Author

Giovanni Resta, Jan 28 2006

Keywords

• nonn

Comments

Double factorials 0!! and 1!! are not considered distinct. Note that double factorial (n!!) is different from (n!)!.

Examples

			10404 = 102^2 = 1!! + 4!! + 11!!.
		

Crossrefs

Cf. A006882, A115649, A115650, A115651, A025494.