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A115649 Numbers whose square is the sum of distinct double factorials (A006882). 2
1, 2, 3, 4, 5, 7, 8, 11, 13, 20, 21, 31, 38, 62, 63, 65, 66, 70, 72, 102, 107, 109, 120, 125, 217, 218, 238, 240, 373, 382, 387, 427, 439, 834, 840, 890, 915, 1440, 1474, 1638, 1650, 3213, 3220, 3241, 3332, 3540, 5886, 6751, 6855, 13730, 14078, 14911 (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
EXAMPLE
102^2 = 1!! + 4!! + 11!!.
CROSSREFS
Sequence in context: A118083 A241093 A116470 * A191168 A309879 A191166
KEYWORD
nonn
AUTHOR
Giovanni Resta, Jan 28 2006
STATUS
approved

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Last modified June 12 11:18 EDT 2024. Contains 373331 sequences. (Running on oeis4.)