31616

Appears in sequences

• Expansion of 2*x^3/((1-2*x)^2*(1-4*x)).at n=9A000431
• Triangle read by rows: T(n,k) (n >= 1, 0 <= k <= ceiling(n/2)-1) = number of permutations of [n] with k peaks.at n=21A008303
• Number of points of L1 norm 2n in root system version of E_8 lattice.at n=6A010369
• Number of sets S = {a_1, a_2, ..., a_k}, with 1 < a_i < a_j <= n such that no a_j divides the product of all the others.at n=25A023995
• Duplicate of A010369.at n=6A035880
• L1-coordination sequence for E_8 lattice in Construction A version of the lattice.at n=6A045651
• Boris Stechkin's function.at n=41A055004
• Number of primes <= 13^n.at n=5A058191
• Structured rhombic triacontahedral numbers (vertex structure 11).at n=15A100164
• Triangle read by rows: T(n,k) = number of Schroeder (or royal) n-paths (A006318) containing k returns to the diagonal y=x. (A northeast step lying on y=x contributes a return.)at n=39A108891
• Expansion of (-1+x^3+x^6+x^9)/((1-x)*(2*x-1)*(x^2+1)*(x^2+x+1)*(x^4-x^2+1)).at n=15A111663
• Triangle read by rows: T(n,k) = 2^k*A123125(n,k).at n=43A141660
• T(n,k) is the number of order-decreasing and order-preserving partial transformations (of an n-chain) of waist k (waist(alpha) = max(Im(alpha))).at n=51A145035
• A triangle related to the a(n) formulas of the rows of the ED3 array A167572.at n=24A167580
• The fourth left hand column of triangle A167580.at n=3A168305
• Triangle T(n,k), read by rows, given by [0,1,2,1,2,1,2,1,2,1,2,...] DELTA [2,0,0,0,0,0,0,0,0,...] where DELTA is the operator defined in A084938.at n=49A172040
• Number of ways to place 2 nonattacking knights on an n X n toroidal board.at n=15A172529
• Number of permutations of length n with no consecutive triples i,i+2,i+4 (mod n) or i,i-2,i-4 (mod n).at n=8A174077
• Numbers k for which 6k+1, 24k+5, 432k^2+72k-1, and 432k^2+90k-1 are all prime.at n=32A175513
• Number of ways to place 2 nonattacking kings on an n X n toroidal board.at n=15A179403