20130

Appears in sequences

• (s(n)+s(n+1))/6, where s()=A006521.at n=20A016059
• (s(n)+s(n+1))/18, where s()=A006521.at n=25A016060
• Number of partitions of n with equal number of parts congruent to each of 0, 1 and 2 (mod 3).at n=60A046765
• Number of partitions of n with equal nonzero number of parts congruent to each of 0, 1 and 2 (mod 3).at n=60A046777
• Ordered m for which m = k^3*a*b*(a^4 - b^4) determine (unique) solution triples(k,a,b), where k=1,2,3,... and (a,b) are coprime pairs, not both odd (i.e., of opposite parity).at n=18A081779
• Numbers n such that the denominator of the 2n-th Bernoulli number is divisible by n but sum_{d|n} sigma(d)/phi(d) is not an integer.at n=12A099008
• Numbers n such that n divides the denominator of 2n-th Bernoulli number.at n=35A106741
• a(n) = (n^3 + 4*n^2 - n)/2.at n=32A162260
• Triangle read by rows: T(n,k) = t(n-k, k); t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = 3*x + 5.at n=12A257624
• Number of nX4 0..1 arrays with every element equal to 0 or 1 horizontally or antidiagonally adjacent elements, with upper left element zero.at n=13A301786
• a(n) = 159*2^n - 222 (n>=1).at n=6A304515
• Expansion of e.g.f. (1/x) * Series_Reversion( x*(1 + log(1-x))^3 ).at n=4A376393