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Powerful(1) numbers (A001694) which are the sum of distinct double factorials (A006882).
5

%I #5 Mar 30 2012 17:40:35

%S 1,4,8,9,16,25,27,49,64,72,108,121,125,128,169,392,400,432,441,500,

%T 512,961,968,972,1125,1331,1352,1444,3844,3888,3969,4225,4232,4356,

%U 4900,4913,5184,5292,5324,10404,10800,10952,11449,11881,14283,14400

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

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

%H <a href="/index/Pow#powerful">Index entries for sequences related to powerful numbers</a>

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

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

%K nonn

%O 1,2

%A _Giovanni Resta_, Jan 28 2006