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A115648 Square numbers which are the sum of distinct double factorials (A006882). 2
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 (list; graph; refs; listen; history; text; internal format)
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..38.

EXAMPLE

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

CROSSREFS

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

Sequence in context: A063735 A056798 A036454 * A082522 A279096 A299153

Adjacent sequences:  A115645 A115646 A115647 * A115649 A115650 A115651

KEYWORD

nonn

AUTHOR

Giovanni Resta, Jan 28 2006

STATUS

approved

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Last modified April 5 06:13 EDT 2020. Contains 333238 sequences. (Running on oeis4.)