21546

Appears in sequences

• a(n) = (2*n+1)*(11*n+1).at n=31A033575
• Write cosec x = 1/x + Sum e_n x^(2n-1)/(2n-1)!; sequence gives denominators of e_n.at n=26A036283
• McKay-Thompson series of class 33B for Monster.at n=42A058637
• a(n) = 3*(n - 2)*(5*n -11).at n=38A060785
• Stirling2 triangle with scaled diagonals (powers of 9).at n=33A075504
• Sixth column of triangle A075504.at n=2A076012
• Numbers n which when converted to base 8, reversed and converted back to base 10 yield a number m such that n mod m = 0. Cases which are trivial or result in digit loss are excluded.at n=7A091082
• First differences of A000043.at n=28A134458
• a(n) = n^3 - n*(n+1)/2.at n=28A160378
• Number of nondecreasing arrangements of 5 nonzero numbers in -(n+3)..(n+3) with sum zero.at n=18A188335
• a(n) = n * A002445(n).at n=27A228838
• Number of asymmetric Lucas strings of length n.at n=20A250113
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 30", based on the 5-celled von Neumann neighborhood.at n=40A269755
• Number of 3-regular bipartitions of n.at n=24A328547
• a(n) = denominator(4^(n + 1)*zeta(-n, 1/4)).at n=53A344918
• a(n) is the number of 4 element sets of distinct integer sided trapezoids whose base angles are 60 degrees that fill an equilateral triangular grid of side n units.at n=47A389392