28620
domain: N
Appears in sequences
- Second convolution of A001405 (central binomial numbers).at n=12A054442
- Numbers n such that n | sigma_13(n).at n=32A055717
- Triangle read by rows: T(n,k) is the coefficient of t^k (k>=0) in the polynomial P[n,t] defined by P[1,t] = P[2,t] = 1, P[3,t] = 1+t, P[n,t] = P[n-1,t] + P^2[n-2,1] for n >= 4.at n=34A103525
- Averages of twin primes such that p1*p2 -+ AverageTwinPrime are primes.at n=8A154668
- Partial sums of A160410.at n=30A160799
- Number of n X 4 0..1 arrays with rows and antidiagonals unimodal and columns nondecreasing.at n=15A224142
- Szeged index of the grid graph P_3 X P_n.at n=14A245827
- Exponential (2,4)-perfect numbers: numbers m such that esigma(esigma(m)) = 4m, where esigma(m) is the sum of exponential divisors of m (A051377).at n=13A328133