13421773

Appears in sequences

• Expansion of (1-x)/(1-2*x+x^2-2*x^3).at n=25A007909
• Expansion of 1/((1-2*x)*(1+x^2)).at n=24A007910
• a(n) = (1 - (-4)^n)/5.at n=12A014985
• Gaussian binomial coefficient [ n,12 ] for q=-4.at n=1A015425
• a(n) = 3*a(n-1) + 4*a(n-2), a(0) = 0, a(1) = 1.at n=13A015521
• Cyclotomic polynomials at x=4.at n=26A019322
• Cyclotomic polynomials at x=-4.at n=13A020503
• Zsigmondy numbers for a = 4, b = 1: Zs(n, 4, 1) is the greatest divisor of 4^n - 1^n (A024036) that is relatively prime to 4^m - 1^m for all positive integers m < n.at n=25A064080
• a(n) = (lcm_{k=0..n} (2^k + 1))/(lcm_{k=0..n-1} (2^k + 1)).at n=25A066845
• a(n) = sigma_4(n^4)/sigma_2(n^4).at n=7A077457
• Triangular array read by rows: row s contains integers of the form (2^s+1)/(2^r+1) in order of increasing r <= s-1.at n=27A079665
• Record values in A091023.at n=12A091052
• Strong pseudoprimes (base-2) equal to product of 3 primes not necessarily distinct.at n=22A112450
• a(n) = a(n-1) + 2^(k(n)), where k(n) is the n-th term of the sequence formed by k(1)=0 together with the numbers A042964.at n=12A113876
• Row sums of triangle A118407.at n=51A118408
• a(n) is the maximal overpseudoprime q to base 2 such that the multiplicative order of 2 mod q equals A143584(n).at n=17A131952
• a(n) = 2*a(n-1) - a(n-2) + 2*a(n-3).at n=24A133190
• a(n) = 3*a(n-1) + 4*a(n-2) - a(n-3) + 3*a(n-4) + 4*a(n-5).at n=12A135343
• a(n) = 3*a(n-1) + 4*a(n-2) - a(n-3) + 3*a(n-4) + 4*a(n-5).at n=12A135345
• Numbers k (between 2^(m-1) and 2^m) such that 2^(k-1) == 1 (mod k) and 2^(k-1-m) == k - 2^p (mod k) for some p > 0 with 2^p < k.at n=33A167612