27057

Appears in sequences

• Number of 3 X 3 integer matrices with elements in the range [ -n,n ] which represent a rotation of order 2.at n=13A053171
• Numbers k such that k^4 == 1 (mod 5^5).at n=34A056102
• E.g.f.: A(x) = exp( Sum_{n>=1} 2^(n(n-1)/2) * x^n/n ).at n=5A171777
• Constant term of the reduction by x^2 -> x+1 of the polynomial p(n,x) defined below in Comments.at n=18A192746
• Numbers n such that n^2 + 1 is divisible by a 5th power.at n=17A218564
• Construct sequences P,Q,R by the rules: Q = first differences of P, R = second differences of P, P starts with 1,3,9, Q starts with 2,6, R starts with 4; at each stage the smallest number not yet present in P,Q,R is appended to R. Sequence gives P.at n=48A225385
• E.g.f. satisfies: A(x) = 1 + A(x)^4 * Integral 1/A(x)^3 dx.at n=5A234293
• a(n) is the sum of quadratic nonresidues of A002145(n) (the n-th prime == 3 mod 4).at n=33A282036
• Let p = n-th prime == 7 mod 8; a(n) = sum of quadratic nonresidues mod p.at n=16A282043
• Numbers k such that k![4] - 1024 is prime, where k![4] = A007662(k) = quadruple factorial.at n=38A329184