# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a078796 Showing 1-1 of 1 %I A078796 #14 Aug 17 2022 22:20:29 %S A078796 1,3,3,5,6,6,8,8,9,11,11,13,14,14,16,16,17,19,19,21,21,22,24,24,26,27, %T A078796 27,29,29,30,32,32,34,35,35,37,37,39,40,40,42,42,43,45,45,47,48,48,50, %U A078796 50,51,53,53,55,55,56,58,58,60,61,61,63,63,64,66,66,68,69,69,71,71,73 %N A078796 a(n) = 2*ceiling(n*tau) - ceiling(n*sqrt(5)) where tau=(1+sqrt(5))/2 is the Golden ratio. %F A078796 a(A005652(n)) = A005652(n); a(A001950(n)) = A001950(n) + 1. %t A078796 Table[2*Ceiling[n*GoldenRatio]-Ceiling[n*Sqrt[5]],{n,80}] (* _Harvey P. Dale_, Dec 20 2015 *) %o A078796 (PARI) a(n)=2*ceil(n*(1+sqrt(5))/2)-ceil(n*sqrt(5)) %o A078796 (Python) %o A078796 from math import isqrt %o A078796 def A078796(n): return (n+(m:=isqrt(5*n**2))&-2)-m+1 # _Chai Wah Wu_, Aug 17 2022 %Y A078796 Cf. A001950, A005652, A078588. %K A078796 nonn %O A078796 1,2 %A A078796 _Benoit Cloitre_, Dec 05 2002 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE