A115651 Powerful(1) numbers (A001694) which are the sum of distinct double factorials (A006882).

1, 4, 8, 9, 16, 25, 27, 49, 64, 72, 108, 121, 125, 128, 169, 392, 400, 432, 441, 500, 512, 961, 968, 972, 1125, 1331, 1352, 1444, 3844, 3888, 3969, 4225, 4232, 4356, 4900, 4913, 5184, 5292, 5324, 10404, 10800, 10952, 11449, 11881, 14283, 14400

Offset

1,2

Comments

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

Links

Table of n, a(n) for n=1..46.

Index entries for sequences related to powerful numbers

Example

392 = 2^3*7^2 = 8!! + 4!!.

Crossrefs

Cf. A001694, A006882, A115652, A115653, A115654.

Sequence in context: A002760 A355062 A355060 * A062559 A010417 A155568

Adjacent sequences: A115648 A115649 A115650 * A115652 A115653 A115654

Keyword

nonn

Author

Giovanni Resta, Jan 28 2006

Status

approved