login
Triangular numbers which are the sum of distinct double factorials (A006882).
2

%I #2 Mar 30 2012 17:40:35

%S 1,3,6,10,15,21,28,66,105,120,153,171,435,561,946,1378,1485,3916,4005,

%T 4278,4851,4950,11781,14365,15576,47586,50086,51360,57970,60378,60726,

%U 61425,61776,139128,145530,146070,149878,150426,182710,659526,702705

%N Triangular numbers 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!)!.

%e T(527) = 19128 = 13!! + 10!! + 7!! + 6!!.

%Y Cf. A006882, A115648, A115649.

%K nonn

%O 1,2

%A _Giovanni Resta_, Jan 28 2006