-647

Appears in sequences

• sec(sin(arcsinh(x)))=1+1/2!*x^2-3/4!*x^4+21/6!*x^6-647/8!*x^8...at n=4A012044
• a(n) = (a(n-1)a(n-5) + a(n-2)a(n-4) + a(n-3)^2)/a(n-6).at n=49A058232
• Expansion of (1+x^2)/(1+x^2+x^5).at n=51A088002
• Define E(n) = Sum_{k>=0} (-1)^floor(k/3)*k^n/k! for n = 0,1,2,... . Then E(n) is an integral linear combination of E(0), E(1) and E(2). This sequence lists the coefficients of E(1).at n=9A143629
• INVERT transform of A002321, Mertens's function.at n=19A144031
• Primes or negative values of primes of the form 8*n^2 - 298*n + 2113 for n >= 0.at n=20A217439
• Primes or negative values of primes of the form 8*n^2 - 326*n + 2659 for n >= 0.at n=19A217440
• First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 489", based on the 5-celled von Neumann neighborhood.at n=19A272513
• First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 493", based on the 5-celled von Neumann neighborhood.at n=15A272546
• Expansion of exp( Sum_{n>=1} -sigma(6*n)*x^n/n ) in powers of x.at n=17A283164
• a(n) = -n^2 + 21*n - 1.at n=37A332884
• Product_{n>=1} 1 / (1 - a(n)*x^n) = 1 + Sum_{n>=1} sigma(n)*x^n, where sigma = A000203.at n=25A353947
• Numerator generator for offsets from the quarter points of the Cantor ternary set to the center points of deleted middle thirds: 1 is in the list and if m is in the list -3m-4 and -3m+4 are in the list, which is ordered by absolute value.at n=26A355680