19966

Appears in sequences

• a(n) = (2*n+1)*(9*n+1).at n=33A033573
• a(1) = 2; a(n) = half of the a(n-1)-th even nontotient number.at n=10A072416
• Number of base 20 circular n-digit numbers with adjacent digits differing by 1 or less.at n=8A124713
• a(n) = Sum_{k=0..n} binomial(n+k,k)*sin(Pi*(n+k)/2).at n=9A181933
• Coefficient of x in the reduction by x^2 -> x+1 of the polynomial p(n,x) defined at Comments.at n=16A192389
• Number of n X 5 arrays of the minimum value of corresponding elements and their horizontal or diagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..1 n X 5 array.at n=23A220029
• Number of unlabeled simple graphs with n edges rooted at two noninterchangeable vertices.at n=8A339063
• 11-gonal numbers which are products of three distinct primes.at n=17A354446
• a(n) is the smallest n-gonal number with binary weight n.at n=8A358930
• G.f. satisfies A(x) = 1 + x^5*A(x)^2 / (1 - x*A(x)).at n=27A365699