20867

Appears in sequences

• Sum of the first n Sophie Germain primes.at n=43A066819
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 497", based on the 5-celled von Neumann neighborhood.at n=29A272558
• Relative of Hofstadter Q-sequence: a(n) = max(0, n+20830) for n <= 0; a(n) = a(n-a(n-1)) + a(n-a(n-2)) + a(n-a(n-3)) for n > 0.at n=36A283887
• Solution of the complementary equation a(n) = 2*a(n-1) - a(n-2) + b(n-1) + 3, where a(0) = 1, a(1) = 2, b(0) = 3, and (a(n)) and (b(n)) are increasing complementary sequences.at n=44A294871
• Expansion of 1/(1 + x*Product_{k>=1} 1/(1 - x^k)).at n=42A318581
• Number of partitions of n with up to five distinct kinds of 1.at n=30A320692
• a(n) is the number of permutations p of {1, 2, ..., n} such that for any k in 1..n, k and p(k) share a common 1-bit.at n=10A352857
• Number of ways to tile a hexagonal strip made up of n equilateral triangles, using diamonds and trapezoids.at n=32A374391