Triangle read by rows: a(n,k)=number of permutations in S_n which avoid the pattern 123 and have exactly k descents.
1, 1, 1, 1, 0, 4, 1, 0, 2, 11, 1, 0, 0, 15, 26, 1, 0, 0, 5, 69, 57, 1, 0, 0, 0, 56, 252, 120, 1
3 seqfan posts
Sat Aug 21 23:45:05 CEST 2010 [seqfan] Re: Similar sequences A126222 and A166073
Thu Aug 19 12:04:03 CEST 2010 [seqfan] Similar sequences A126222 and A166073
Thu Oct 8 22:53:03 CEST 2009 [seqfan] Dyck paths in A166073 and A091156
Index of A-numbers in seqfan: by ascending order
by month
by frequency
by keyword
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