21789

Appears in sequences

• Number of primitive (aperiodic) step shifted (decimated) sequence structures using a maximum of five different symbols.at n=9A056404
• a(n) = A077696(n+1)/A077696(n).at n=28A077697
• a(n) = n^3 + 6*n^2 + 6*n + 1.at n=26A090197
• Sum of the squares of the first n nonsquarefree numbers (A013929).at n=20A111732
• Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 10000-11111-10000 pattern in any orientation.at n=13A147078
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, -1), (-1, -1, 0), (-1, 0, -1), (0, -1, -1), (1, 1, 1)}.at n=9A149496
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 0, 1), (-1, 1, 0), (1, 0, -1), (1, 1, 1)}.at n=8A149644
• a(n) = (2*n^3 + 5*n^2 + 21*n)/2.at n=26A162266
• Number of permutations of 1..n with displacements restricted to {-5,-4,0,1,2,3}.at n=12A189592
• Augmentation of the triangular array A158405. See Comments.at n=49A193091
• Number of ordered triples (w,x,y) with all terms in {1,...,n} and w^2+x^2+y^2>2n.at n=28A211644
• Number of representations of n as a sum of products of pairs of positive integers, n = Sum_{k=1..m} i_k*j_k with i_k<=j_k, i_k<=i_{k+1}, j_k<=j_{k+1}, i_k*j_k<=i_{k+1}*j_{k+1}.at n=35A212214
• Number of length 2+4 0..n arrays with every five consecutive terms having four times some element equal to the sum of the remaining four.at n=9A249658
• Molien series for invariants of finite Coxeter group A_9.at n=61A266778
• If n^2 has an even number of digits, write n after the left half of the digits of n^2 and before the right half, otherwise if n^2 has 2t+1 digits, write n after the first t digits of n^2 and before the last t+1 digits.at n=16A274620
• The number of n-digit numbers k such that k + digit reversal of k (A056964) is a square.at n=8A358984
• Expansion of Sum_{k>0} (1/(1-x^k)^6 - 1).at n=15A363696
• a(n) = sum for all integer partitions of n of the difference between number of different parts and number of different multiplicities.at n=33A373243