A228186 a(n) is the smallest natural number k such that (k+n+1)!*(k-n-2)! < 2*k!*(k-1)!.

4, 9, 18, 29, 44, 61, 81, 104, 130, 159, 191, 226, 263, 304, 347, 393, 442, 494, 549, 607, 667, 731, 797, 866, 938, 1013, 1091, 1172, 1256, 1342, 1432, 1524, 1619, 1717, 1818, 1922, 2029, 2139, 2251, 2367, 2485, 2606, 2730, 2857, 2987, 3120, 3255, 3394, 3535

Offset

0,1

Links

John Ting, Table of n, a(n) for n = 0..100.

Prog

(PARI) for(n=0, 50, for(k=n+2, oo, if(((k+n+1)!)*((k-n-2)!) < 2* (k!)* ((k-1)!), print1(k, ", "); break))) \\ Hugo Pfoertner, Oct 30 2020 using Adam P. Goucher's definition

Crossrefs

Cf. A100967.

Sequence in context: A101424 A301197 A008021 * A103976 A301257 A036695

Adjacent sequences: A228183 A228184 A228185 * A228187 A228188 A228189

Keyword

nonn

Author

John Ting, Aug 15 2013

Extensions

Entry revised by N. J. A. Sloane, Oct 30 2020, incorporating a more precise definition from Adam P. Goucher

Status

approved