48756

Appears in sequences

• Number of permutations of [n] containing exactly 2 increasing subsequences of length 3.at n=10A001089
• Least k such that the first k terms of A006928 contain n more 2's than 1's.at n=25A025507
• a(n) = A053141(n)/2.at n=7A053142
• Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 3 X 3 which is symmetric after a rotation by 180 degrees.at n=7A123833
• Number of ways to place 2 nonattacking bishops on an n X n board.at n=17A172123
• A q-form product triangle based on:q=2;a(n, q)= (Sum[(1 + (-1)^n)*(1 + Sqrt[q])^m, {m, 1, n}] + Sum[(1 + (-1)^n)*(1 - Sqrt[q])^m, {m, 1, n}])/4.at n=29A173584
• A q-form product triangle based on:q=2;a(n, q)= (Sum[(1 + (-1)^n)*(1 + Sqrt[q])^m, {m, 1, n}] + Sum[(1 + (-1)^n)*(1 - Sqrt[q])^m, {m, 1, n}])/4.at n=34A173584
• Triangle T(n,k) read by rows: T(n,k) = number of permutations on 123...n with exactly two abc patterns and no aj pattern with j<=k, for n>=0, 0<=k<=n.at n=55A229158
• Triangle T(n,k) read by rows: T(n,k) = number of permutations on 123...n with exactly two abc patterns and no aj pattern with j<=k, for n>=0, 0<=k<=n.at n=56A229158
• Numerator of Sum_{i=1..n} n^i/i.at n=5A237872
• Indices in A006928 where the imbalance between 1's and 2's sets a new record.at n=38A274775
• a(n) appears in the congruences modulo 4 or 32 of Markoff numbers m(n) = A002559(n) for odd or even m(n).at n=32A309376
• Expansion of Sum_{k>0} x^(4*k)/(1-x^k)^5.at n=33A363608