A189786 a(n) = n + [nr/t] + [ns/t]; r=Pi/2, s=arcsin(5/13), t=arcsin(12/13).

2, 4, 8, 10, 12, 16, 18, 20, 24, 26, 28, 32, 34, 36, 40, 42, 44, 48, 50, 52, 56, 58, 60, 64, 66, 68, 72, 74, 76, 80, 82, 84, 88, 90, 92, 96, 98, 100, 104, 106, 108, 112, 114, 116, 120, 122, 124, 128, 130, 132, 136, 138, 140, 144, 146, 148, 152, 154, 156, 160, 162, 164, 168, 170, 172, 176, 178, 180, 184, 186, 188, 192, 194, 196, 200, 202, 204

Offset: 1

Author

Clark Kimberling, Apr 27 2011

Keywords

• nonn
• changed

Comments

See A189785.

Conjecture: Sequence consists of all the positive even numbers except numbers of the form 8*x+6, x >= 0. - Harvey P. Dale, Dec 07 2018

Contains numbers like a(143)=382, a(146)=390, a(149)=398, a(152)=406,... which are not in A047464. - R. J. Mathar, Aug 25 2025

For n<143, a(n) = n+A047217(n+1), but then this formula becomes invalid. - R. J. Mathar, Aug 25 2025

Crossrefs

Cf. A189785, A189787.

Programs

Mathematica

(See A189785.)
With[{t=ArcSin[12/13]},Table[n+Floor[(n*Pi/2)/t]+Floor[(n*ArcSin[5/13])/t],{n,80}]] (* Harvey P. Dale, Dec 07 2018 *)