20049

Appears in sequences

• Expansion of 1/((1-x)^3 (1-x^2)^2 (1-x^3) (1-x^4)).at n=23A002626
• a(n) = n*(2*n^2 + 1)*(n^2 + 1)/6.at n=8A052459
• Positions of highly powerful numbers in the EKG sequence.at n=20A141422
• Row sums of triangle A145370 (S1hat(-4)) and partition array A145359 (M31hat(-4)).at n=9A145371
• 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, 0), (0, -1, 0), (0, 1, -1), (1, 1, 1)}.at n=8A149681
• Number of UH^jU's, DH^jD's, and DH^jU's for some j>0, in all peakless Motzkin paths of length n (here U=(1,1), D=(1,-1) and H=(1,0); can be easily expressed using RNA secondary structure terminology).at n=14A187259
• Number of (w,x,y) with all terms in {0,...,n} and |w-x| + |x-y| > w+x+y.at n=27A213482
• Numbers k such that phi(x) = 12*k+2 is solvable, where phi is Euler's totient A000010.at n=26A289364
• Numbers k for which A354102(k) = A354102(sigma(k)).at n=17A354106
• Table read by antidiagonals: Place k equally spaced points on each side of a regular n-gon and join every pair of these n*k points by a chord; T(n,k) (n >= 3, k >= 0) gives the number of regions in the resulting planar graph.at n=40A367304
• a(n) = Sum_{k=0..n} 4^k * binomial(n,k) * binomial(n+3,k).at n=4A388206