a(n) = Sum_{i=0..n, j=0..n} (binomial(2*i, j) + binomial(2*j, i)).
A324568
a(n) = Sum_{i=0..n, j=0..n} (binomial(2*i, j) + binomial(2*j, i)).
Terms
- a(0) =2a(1) =8a(2) =32a(3) =124a(4) =482a(5) =1882a(6) =7380a(7) =29036a(8) =114530a(9) =452638a(10) =1791638a(11) =7100430a(12) =28167986a(13) =111837902a(14) =444351292a(15) =1766536044a(16) =7026526226a(17) =27960911422a(18) =111308958942a(19) =443258277254
External references
- oeis: A324568