8257536

Appears in sequences

• Denominator of beta(2n+1)/Pi^(2n+1), where beta(m) = Sum_{k=0..inf} (-1)^k/(2k+1)^m.at n=4A053005
• Number of divisors of k as k runs through sequence of distinct values of LCM(1,..,n).at n=28A056795
• Half totient of 2^n+1.at n=23A063474
• Denominator of S(n)/Pi^n, where S(n) = Sum((4k+1)^(-n),k,-inf,+inf).at n=8A068205
• 20-almost primes (generalization of semiprimes).at n=14A069281
• a(1) = 1; a(n) is the smallest multiple of a(n-1) not divisible by 10 which is greater than the digit reversal of a(n-1). In case R(a(n-1)) < a(n-1) then a(n) = 2*a(n-1).at n=17A076086
• Number of Pythagorean triples mod 2^n; i.e., number of solutions to x^2 + y^2 = z^2 mod 2^n.at n=11A091143
• Smallest number beginning with 8 and having exactly n prime divisors counted with multiplicity.at n=19A106428
• Triangle T, read by rows, where matrix power T^-2 has -2^(n+1) in the secondary diagonal: [T^-2](n+1,n) = -2^(n+1), with all 1's in the main diagonal and zeros elsewhere.at n=30A117265
• a(n) = binomial(n + 5, 5) * 8^n.at n=5A173155
• Triangle read by rows: terms T(n,k) of a binomial decomposition of n*(-1)^n as Sum(k=0..n)T(n,k).at n=51A244141
• a(n) is the number of numbers whose largest prime power factor equals A000961(n).at n=29A305215
• Numbers that can be written in two or more ways as the product of three divisors greater than 1 such that the number in binary is contained in the string concatenation of the divisors in binary.at n=30A356143