21628

Appears in sequences

• Denominators of continued fraction convergents to sqrt(347).at n=12A041657
• a(n) = smallest number > a(n-1) such that a(1)*a(2)*...*a(n) + 1 and a(1)*a(2)*...*a(n) - 1 are primes.at n=42A051956
• Numbers equal to a permutation (or rearrangement) of the digits of the sum of their proper divisors. Rearrangements which cause leading zeros are excluded.at n=22A085844
• Array: row n shows the coefficients of the characteristic polynomial of the n-th principal submatrix of (f(i,j)), where f(i,j)=(2i-1 if max(i,j) is odd, and 0 otherwise) as in A204173.at n=47A204174
• If n is 0, 1, or prime, a(n) = n; else a(n) = a(n-1) + a(n-2).at n=42A265822
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 630", based on the 5-celled von Neumann neighborhood.at n=35A269543
• a(n) = a(n-1) + a(n-2) + a([n/3]), where a(0) = 1, a(1) = 2, a(2) = 3.at n=19A298341