a(n) = floor(Sum_{k=0..n} k!/2), or floor( A003422(n+1)/2 ).
A014288
a(n) = floor(Sum_{k=0..n} k!/2), or floor( A003422(n+1)/2 ).
Terms
- a(0) =0a(1) =1a(2) =2a(3) =5a(4) =17a(5) =77a(6) =437a(7) =2957a(8) =23117a(9) =204557a(10) =2018957a(11) =21977357a(12) =261478157a(13) =3374988557a(14) =46964134157a(15) =700801318157
External references
- oeis: A014288