A083080 Main diagonal of number array A083075.

1, 3, 33, 547, 11713, 309411, 9763393, 359046339, 15096500481, 714852041923, 37660464739681, 2185503641764323, 138548894120306881, 9527726662032987747, 706481006206076565633, 56192761405186331759491, 4772652023437643612132353, 431127499669033202326138755

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..300

Formula

a(n) = (n*(2n+3)^n + 1)/(n+1).

a(n) ~ exp(3/2-9/(8*n)) * (2*n)^n. - Amiram Eldar, Feb 05 2026

Mathematica

a[n_] := (n*(2n+3)^n + 1)/(n+1); Array[a, 20, 0] (* Amiram Eldar, Feb 05 2026 *)

Prog

(Magma) [(n*(2*n+3)^n+1)/(n+1): n in [0..20]]; // Vincenzo Librandi, Nov 12 2011

Crossrefs

Cf. A083075, A083081, A083082.

Sequence in context: A291818 A209245 A092170 * A395576 A002916 A009659

Adjacent sequences: A083077 A083078 A083079 * A083081 A083082 A083083

Keyword

easy,nonn

Author

Paul Barry, Apr 23 2003

Status

approved