160400

Appears in sequences

• Expansion of e.g.f.: exp(tan(sinh(x))).at n=9A009239
• Expansion of sin(tanh(sin(x))).at n=4A009520
• Sum of distinct powers of 20; i.e., numbers with digits in {0,1} base 20; i.e., write n in base 2 and read as if written in base 20.at n=20A063012
• Numbers k such that core(k) = ceiling(sqrt(k)) where core(k) is the squarefree part of k (the smallest integer such that k*core(k) is a square).at n=18A069187
• a(n) = n^2*(n^2+1).at n=20A071253
• Replace 2^i with n^i in binary representation of n.at n=19A104258
• a(1) = 1, a(2*n) = a(n)^2, a(2*n+1) = a(n)*(a(n)+1).at n=52A139145
• Let the binary expansion of n be [b_d, b_{d-1}, ..., b_3, b_2, b_1, b_0]_2, where (if n>0) b_d = 1, b_i = 0 or 1 for i<d. To get a(n) concatenate the decimal numbers 2^(b_i) (if b_i = 1) or 0 (if b_i = 0).at n=20A302205
• Primitive numbers that are the sum of the squares of two of their distinct divisors.at n=35A338485
• a(n) = Sum_{p|n, p prime} n^phi(n/p).at n=19A369782
• a(n) = Sum_{p|n, p prime} n^pi(n/p).at n=19A369868