6815744

Appears in sequences

• a(n) = 13*2^n.at n=19A005029
• a(n) = T(n,2), array T as in A049600.at n=18A049611
• Expansion of (1+3*x+4*x^2)/(1-4*x^2+4*x^4).at n=34A058582
• a(n) = n! reduced mod 2^n.at n=22A068496
• 20-almost primes (generalization of semiprimes).at n=12A069281
• Binomial transform of binomial(n+2,2).at n=17A084851
• Third differences of A129952.at n=20A129955
• a(n) = (3*n+1)*2^n.at n=17A130129
• 3-level binary fanout graph coloring a rectangular array: number of nX1 0..6 arrays where 0..6 label nodes of a graph with edges 0,1 1,3 1,4 0,2 2,5 2,6 and every array movement to a horizontal or vertical neighbor moves along an edge of this graph.at n=20A223417
• G.f. satisfies: A(x) = exp( Sum_{n>=1} [Sum_{k=0..2*n} T(n,k)^2 * x^k] / A(x)^n * x^n/n ), where T(n,k) is the coefficient of x^k in (1 + x + 2*x^2)^n.at n=37A251687
• Row sums of A146565.at n=23A259098
• Consider the Watanabe tag system defined in A291067; a(n) = number of binary words of length n which terminate at the empty word.at n=23A291780
• Numbers k such that k and phi(k) are in A292544.at n=2A303643
• Assuming the truth of the Collatz conjecture, let {m, f(m), f(f(m)), ..., 1} be the set where f is the Collatz function. The sequence lists the numbers m such that m/phi(m) + f(m)/phi(f(m)) + f(f(m))/phi(f(f(m))) + ... + 1/phi(1) is an integer, where phi is the Euler totient function A000010.at n=27A319385