-3023

Appears in sequences

• Expansion of exp(x)/cos(log(1+x)).at n=7A009288
• Generalized sum of divisors function: third diagonal of A060044.at n=30A060045
• a(n) is the numerator of b(n): b(1)=2. b(n) be such that the continued fraction (of +-rational terms) [b(1); b(2), ..., b(n)] = Sum_{k=1..n-1} 1/b(k), for every integer n >= 2.at n=6A128776
• Triangle read by rows: t(n,m) = Sum_{i=0..n} (-1)^(m-i)*Eulerian1(n-i+1, m-i) *Stirling2(n+i+1, i+1), where Eulerian1 are the Eulerian numbers of the first kind (A173018).at n=23A156364
• a(n)=1-4*n-4*n^2.at n=27A184882
• First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 261", based on the 5-celled von Neumann neighborhood.at n=27A271064
• First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 377", based on the 5-celled von Neumann neighborhood.at n=33A271464