20181

Appears in sequences

• a(n) = 21*n^2.at n=31A064762
• Triangle read by rows: matrix product of the Stirling numbers of the second kind with the binomial coefficients.at n=40A126351
• Number of base 13 n-digit numbers with adjacent digits differing by three or less.at n=5A126481
• Triangle read by rows: 2-Stirling numbers of the second kind.at n=40A143494
• L-matrix for Euler numbers A000111(n+1).at n=40A147315
• Totally multiplicative sequence with a(p) = 10p+1 for prime p.at n=17A166668
• Expansion of (6*x + 1) / ((x - 1)*(2*x - 1)*(4*x - 1)*(8*x - 1)).at n=4A177730
• Triangle read by rows, T(n,k) = Sum_{j=0..n} (-1)^(n-j)*C(-j,-n)*S2(j,k), S2 the Stirling set numbers A048993, for n>=0 and 0<=k<=n.at n=50A269952
• E.g.f.: exp(x) * (BesselI(0,8*x) + BesselI(1,8*x)).at n=5A349541
• Triangle read by rows. The incomplete Bell transform of the swinging factorials A056040.at n=50A352363
• Expansion of Sum_{k>0} x^(3*k)/(1-x^k)^4.at n=47A363607
• Triangular array read by rows. T(n,k) is the number of labeled posets on [n] of rank at most one with exactly k elements of positive indegree, n >= 0, 0 <= k <= max{0,n-1}.at n=24A369919
• a(n) = sigma_1(n) * sigma_2(n).at n=24A379812
• E.g.f. A(x) satisfies A(x) = exp(x*C(x*A(x)^3)), where C(x) = 1 + x*C(x)^2 is the g.f. of A000108.at n=5A382042