20912

Appears in sequences

• Numbers whose base-12 representation has exactly 5 runs.at n=18A043654
• Interprimes which are of the form s*prime, s=16.at n=18A075291
• Expansion of 1/( (1-x)*(1 + x^2 + x^3) ).at n=54A077889
• Number of transitions necessary for a Turing machine to compute the differences between consecutive primes (primes written in unary), when using the instruction table below.at n=25A078612
• Even Padovan numbers divided by 2.at n=19A135619
• a(n) = ceiling(A000931(n)/2).at n=40A173692
• Number of nondecreasing arrangements of n+2 numbers in 0..6 with each number being the sum mod 7 of two others.at n=10A183909
• Number of 2 X 2 matrices with all elements in {0,1,...,n} and determinant in {0,1,...,n}.at n=21A209995
• Numbers equal to the arithmetic derivative of their Euler totient function.at n=41A248815
• Smallest k such that A285481(k) >= n, i.e., lowest d where the smallest integer radius needed for a d-dimensional ball to have a volume >= 1 is at least n.at n=35A285482
• Even composite integers m such that A006190(m)^2 == 1 (mod m).at n=9A337235
• Expansion of sqrt(1 - 4*x*sqrt(1 - 4*x)).at n=11A377243
• Number of subsets of Z_n such that every ordered pair of distinct elements has a different sum.at n=22A382400