[seqfan] Re: A066411

[Ron Hardin]

I get 1 1 3 5 23 61 143 215 995 2481 5785 12907 29279 64963 144289 158049 which 
agrees with the series.

Time in C on a not very fast laptop for the last 3 terms

37h 30m
01h 33m
00h 05m

The method was representing it as a sum of a product of 0..n with binomial 
coefficients,
sort the binomial coefficients smallest first,
apply the permutations of 0..15 to these in turn getting a cumulative sum at 
each level,
look at each level L whether this set of L elements of 0..15 has been seen 
before together with the same sum,
and if so abort further recursion at that level for that case.

I don't know if this implicitly takes into account all the symmetries talked 
about.

One that sounds new is converting a n! problem into a 2^n problem, providing the 
sums repeat, which is encouraged by taking the smallest coefficients first.

Remembering what has occurred already was subject to cache dumping at the 
highest levels first, though I don't think that happened.

 rhhardin at mindspring.com
rhhardin at att.net (either)