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a(n) = ceiling(n*phi^2), where phi is the golden ratio, A001622.
9

%I #22 Feb 22 2023 05:36:01

%S 0,3,6,8,11,14,16,19,21,24,27,29,32,35,37,40,42,45,48,50,53,55,58,61,

%T 63,66,69,71,74,76,79,82,84,87,90,92,95,97,100,103,105,108,110,113,

%U 116,118,121,124,126,129,131,134

%N a(n) = ceiling(n*phi^2), where phi is the golden ratio, A001622.

%H Reinhard Zumkeller, <a href="/A004957/b004957.txt">Table of n, a(n) for n = 0..10000</a>

%F A060142(a(n)) = 4 * A060142(n). - _Reinhard Zumkeller_, Nov 26 2012

%o (Haskell)

%o import Data.List (findIndices)

%o a004957 n = a004957_list !! n

%o a004957_list = findIndices even a060142_list

%o -- _Reinhard Zumkeller_, Nov 26 2012

%Y Essentially same as A026352.

%Y Cf. A001622.

%K nonn

%O 0,2

%A _N. J. A. Sloane_