21872

Appears in sequences

• Number of points on surface of dodecahedron: a(n) = 30*n^2 + 2 for n > 0.at n=27A005903
• Numbers k such that 90*R_k + 7 is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=10A056662
• a(n) = 3*a(n-1) - 2*a(n-2) - a(n-3) + a(n-4) with n>3, a(0)=1, a(1)=2, a(2)=3, a(3)=6.at n=19A131269
• Number of nondecreasing -n..n vectors of length 3 whose dot product with some nonincreasing -n..n vector equals 3.at n=25A226400
• Numbers equal to the arithmetic derivative of their Euler totient function.at n=43A248815
• Number of distinct values of |product(A) - product(B)| where A and B are a partition of {1,2,...,n}.at n=21A263292
• a(n) = [x^n] Product_{k=1..n} 1/(1 + x^k)^(n-k+1).at n=10A303174
• a(n) = n! [x^n] exp(2*x)*(y*sinh(x*y) + cosh(x*y)) and y = sqrt(x).at n=8A335537
• Fixed points in A097465.at n=16A352096
• Number of integer compositions of 2n whose half-alternating sum is 0.at n=9A357641