A323216 Main diagonal of A323212.

1, 1, 7, 56, 477, 4180, 37401, 339184, 3107583, 28691938, 266537777, 2488340790, 23326071990, 219416722056, 2070014554612, 19578402111888, 185583671757949, 1762564846962972, 16768616366059543, 159777503753057786, 1524516616304476102, 14564266581096857240

Offset

0,3

Links

Table of n, a(n) for n=0..21.

Formula

a(n) ~ sqrt(1/20 + 11*cos((4*Pi + arccos(105*sqrt(1047)/5324))/3) / (5*sqrt(1047))) * (62/15 + 4*sqrt(781)*cos(arccos(-738431/(49984*sqrt(781)))/3)/15)^n / sqrt(Pi*n). - Vaclav Kotesovec, Jun 06 2026

Mathematica

nmax = 21; T = PadRight[CoefficientList[# + O[y]^(nmax+1), y], nmax+1]& /@ CoefficientList[1 + 2 x (x+1)/(Sqrt[1 - 4 y] - 2 x (x+1) + 1) + O[x]^(nmax+1), x];
a[n_] := T[[n + 1, n + 1]];
Table[a[n], {n, 0, nmax}] (* Jean-François Alcover, Jul 21 2019 *)

Crossrefs

A323212.

Sequence in context: A387009 A305198 A264912 * A024091 A145302 A233669

Adjacent sequences: A323213 A323214 A323215 * A323217 A323218 A323219

Keyword

nonn

Author

Peter Luschny, Mar 18 2019

Status

approved