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a(n) = A000201(n) + A000201(n+2).
2

%I #13 Aug 10 2022 03:07:04

%S 3,5,9,12,15,19,21,25,28,31,35,38,41,45,47,51,54,57,61,63,67,70,73,77,

%T 80,83,87,89,93,96,99,103,106,109,113,115,119,122,125,129,131,135,138,

%U 141,145,148,151,155,157,161,164,167,171,173,177,180,183,187,190,193,197,199,203,206,209,213,216,219,223,225

%N a(n) = A000201(n) + A000201(n+2).

%C See A191402.

%t (See A191402.)

%o (Python)

%o from math import isqrt

%o def A191403(n): return (n+isqrt(m:=5*n**2)>>1)+(n+isqrt(m+(5*(n+1)<<2))>>1)+1 # _Chai Wah Wu_, Aug 10 2022

%Y Cf. A000201, A191402.

%K nonn

%O 0,1

%A _Clark Kimberling_, Jun 01 2011