a(n) = Sum_{k=0..n} binomial(2n+1, 2k)*5^(n-k).
A102592
a(n) = Sum_{k=0..n} binomial(2n+1, 2k)*5^(n-k).
Terms
- a(0) =1a(1) =8a(2) =80a(3) =832a(4) =8704a(5) =91136a(6) =954368a(7) =9994240a(8) =104660992a(9) =1096024064a(10) =11477712896a(11) =120196169728
External references
- oeis: A102592