91136

Appears in sequences

• Number of degree-n irreducible polynomials over GF(2) with trace = 0 and subtrace = 1.at n=22A042979
• Number of degree-n irreducible polynomials over GF(2) with trace = 1 and subtrace = 0.at n=22A042981
• Primitive numbers k that divide sigma(k)*phi(k).at n=19A055196
• a(n) = 2*a(n-1) + 4*a(n-2), a(0)=1, a(1)=2.at n=10A063727
• Number of binary Lyndon words of length n with trace 0 and subtrace 1 over Z_2.at n=22A074028
• Number of binary Lyndon words of length n with trace 1 and subtrace 0 over Z_2.at n=22A074029
• Horadam sequence (0,1,4,2).at n=11A085449
• a(n) = Sum_{k=0..n} binomial(2n+1, 2k)*5^(n-k).at n=5A102592
• Numbers k such that the concatenation of k with 4*k gives a square.at n=15A115535
• Numbers with 22 divisors.at n=22A137485
• Smallest number m such that prime(n) is a factor of both m and sigma(m).at n=23A156099
• a(1) = 1, a(n) = 2*a(n-1) if n is even; a(n) = a(n-1)*Fibonacci((n+1)/2)/Fibonacci((n-1)/2) if n is odd.at n=20A171648
• Number of (n+1)X9 binary arrays with every 2X2 subblock nonsingular.at n=2A183687
• T(n,k)=Number of (n+1)X(k+1) binary arrays with every 2X2 subblock nonsingular.at n=47A183688
• a(n) is the smallest integer m such that n is the least exponent k satisfying sigma(m)^k divides m.at n=9A264155
• Number of subsets of {1, 2, 3, ..., n} that include no consecutive even integers.at n=19A279312
• Number of nX2 0..1 arrays with every element unequal to 0, 1 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.at n=22A317767
• a(n) = [x^n] Product_{k>=1} 1 / (1 - n^(k+1)*x^k).at n=4A344095
• G.f. A(x) satisfies A(x) = sqrt( (1 + 2*x*A(x)^3) * (1 + 2*x*A(x)) ).at n=7A379328