22820

Appears in sequences

• Hexagonal prism numbers: a(n) = (n + 1)*(3*n^2 + 3*n + 1).at n=19A005915
• Theta series of A2[hole]^4.at n=38A033690
• a(n) = a(1) + a(2) + ... + a(n-1) + a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = a(2) = a(3) = 1.at n=15A049932
• Number of positive integers <= 2^n of form 3 x^2 + 8 y^2.at n=18A054165
• Integers k such that 10^k + 67 is a prime number.at n=17A135113
• Number of ways to place 2 nonattacking nightriders on an n X n board.at n=14A172141
• Values of x in A216363.at n=30A216382
• a(n) = n*(n + 1)*(17*n - 14)/6.at n=20A237617
• Number of steps before n1(i) = n2(i) when n1(i) = n1(i-1) + digsum(n2(i-1)), n2(i) = n2(i-1) + digsum(n1(i-1)) and n1(1) = 10^(n-1), n2(1) = 0.at n=3A272233
• Number of distinct ways to erect n semicircles of distinct diameters in [n] on the number line from 1 to 2n using 2 colors where all semicircles of the same color are mutually noncrossing. Two ways are regarded the same if the number line is reversed or the colors are exchanged.at n=15A375254