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a(n) = A000201(n) + A000201(n+1).
4

%I #11 Aug 11 2022 03:21:03

%S 1,4,7,10,14,17,20,23,26,30,33,36,40,43,46,49,52,56,59,62,65,68,72,75,

%T 78,82,85,88,91,94,98,101,104,108,111,114,117,120,124,127,130,133,136,

%U 140,143,146,150,153,156,159,162,166,169,172,175,178,182,185,188,192,195,198,201,204,208,211,214,218,221,224

%N a(n) = A000201(n) + A000201(n+1).

%F a(n) = [nr] + [nr+r], where r=(1+sqrt(5))/2 and [ ]=floor.

%t r = GoldenRatio; f[n_] := Floor[n*r];

%t Table[f[n]+f[n+1], {n,0,100}]

%t (* A191402(n)=A000201(n)+A000201(n+1) *)

%t Table[f[n] + f[n+2], {n, 0, 100}]

%t (* A191403(n)=A000201(n)+A000201(n+2) *)

%t Table[f[n] + f[n+3], {n, 0, 100}]

%t (* A191404(n)=A000201(n)+A000201(n+3) *)

%o (Python)

%o from math import isqrt

%o def A191402(n): return (n+isqrt(m:=5*n**2)>>1)+(n+1+isqrt(m+10*n+5)>>1) # _Chai Wah Wu_, Aug 10 2022

%Y Cf. A191403, A191404.

%K nonn

%O 0,2

%A _Clark Kimberling_, Jun 01 2011