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
Keywords
Links
- John Ting, Table of n, a(n) for n = 0..100.
Crossrefs
Cf. A100967.
Programs
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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
Extensions
Entry revised by N. J. A. Sloane, Oct 30 2020, incorporating a more precise definition from Adam P. Goucher