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%I #12 Nov 24 2022 17:13:50
%S 1,2,5,6,7,8,11,12,15,16,17,18,21,22,23,24,27,28,31,32,33,34,37,38,41,
%T 42,43,44,47,48,49,50,53,54,57,58,59,60,63,64,65,66,69,70,73,74,75,76,
%U 79,80,83,84,85,86,89,90,91,92,95,96,99,100,101,102,105,106,109,110,111
%N Secondary Lower Wythoff Sequence.
%C This sequence is the ordered union of odd numbered columns of the Wythoff secondary array, A137707. See A137707 for complementary equations of which this sequence is a solution.
%F a(2n)=2*A000201(n)=a(2n-1)+1; A000201 is the lower Wythoff sequence.
%e The lower Wythoff sequence begins with 1,3,4,6,8,9,...
%e Double these: 2,6,8,12,16,18...; subtract 1: 1,5,7,11,15,17;
%e Then merge: 1,2,5,6,7,8,11,12,15,16,17,18,...
%o (Python)
%o from math import isqrt
%o def A137708(n): return ((m:=n+1>>1)+isqrt(5*m**2)&-2)-(n&1) # _Chai Wah Wu_, Aug 11 2022
%Y Cf. A035513, A137709.
%K nonn,easy
%O 1,2
%A _Clark Kimberling_, Feb 07 2008
%E a(37)=59 corrected by _Georg Fischer_, Nov 24 2022
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