40156

Appears in sequences

• a(n) = T(2n-1,n-1), T given by A026769. Also T(2n+1,n+1), T given by A026780.at n=7A026773
• a(n) = T(n, floor(n/2)), T given by A026769.at n=15A026775
• Numbers n such that n+1 divides prime(n)+1.at n=13A061437
• 4th binomial transform of (1,0,1,0,1,...), A059841.at n=7A081186
• Indices of primes in sequence defined by A(0) = 89, A(n) = 10*A(n-1) - 21 for n > 0.at n=15A101075
• Numbers k such that prime(k) == 11 (mod k).at n=15A116657
• Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of n steps taken from {(-1, -1), (-1, 0), (0, -1), (0, 1), (1, 1)}.at n=9A151427
• Number of binary strings of length n with no substrings equal to 0001 0110 or 1011.at n=18A164479
• Array T(n,k) read by antidiagonals: T(n,k) = Sum_{v=1..n, v odd} binomial(n,v)*k^v.at n=48A169629
• Fundamental discriminants d uniquely characterizing all complex biquadratic fields Q(sqrt(-3),sqrt(d)) which have 3-class group of type (3,3) and second 3-class group isomorphic to either SmallGroup(2187,247)-#1;5 or SmallGroup(2187,247)-#1;9.at n=13A250242
• Number of 6-cycles in the n X n knight graph.at n=20A289181
• Numbers z such that x^2 + y^7 = z^2 (with positive integers x and y) and gcd(x, y, z) = 1.at n=6A293693
• Expansion of (-1 + Product_{k>=1} 1 / (1 + (-x)^k))^3.at n=42A341241
• Indices of records in A307730.at n=45A348449