OFFSET
1,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..300
FORMULA
a(n) = ((n-1)*(2n+1)^n + 1)/n.
a(n) ~ exp(1/2-1/(8*n)) * (2*n)^n. - Amiram Eldar, Feb 05 2026
MATHEMATICA
Unprotect[Power]; Power[0, 0]=1; Protect[Power]; a[n_]:=((n-1)*(2n+1)^n + 1)/n; Array[a, 15] (* Stefano Spezia, Sep 19 2025 *)
PROG
(Magma) [((n-1)*(2*n+1)^n+1)/n: n in [1..20]]; // Vincenzo Librandi, Nov 12 2011
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Apr 23 2003
STATUS
approved