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%I A026355 #16 Aug 26 2022 02:49:22
%S A026355 1,2,3,5,6,8,10,11,13,14,16,18,19,21,23,24,26,27,29,31,32,34,35,37,39,
%T A026355 40,42,44,45,47,48,50,52,53,55,57,58,60,61,63,65,66,68,69,71,73,74,76,
%U A026355 78,79,81,82,84,86,87,89,90,92,94,95,97,99,100,102,103,105,107,108,110
%N A026355 a(n) = least k such that s(k) = n+1, where s = A026354.
%C A026355 Let f(1)=1, f(2)=q and f(k+2) = f(k+1)+f(k)-n; a(n) is the smallest positive integer q such that f(k) -> infinity as k -> infinity. - _Benoit Cloitre_, Aug 04 2002
%H A026355 J. H. Conway and N. J. A. Sloane, <a href="/A019586/a019586.pdf">Notes on the Para-Fibonacci and related sequences</a>
%F A026355 For n>0, a(n) = floor((n-1)*phi) + 2, where phi=(1+sqrt(5))/2.
%F A026355 Recurrences: a(n+1) = a(n)+(3 + sign(phi*n-a(n)))/2 for n>=0. Also a(n+1) = a(n) + 1 + A005614(n-2) for n>=2. - _Benoit Cloitre_, Aug 04 2002
%o A026355 (Python)
%o A026355 from math import isqrt
%o A026355 def A026355(n): return (n-1+isqrt(5*(n-1)**2)>>1)+2 if n else 1 # _Chai Wah Wu_, Aug 25 2022
%Y A026355 Cf. A000201, A005614, A026351. Different from A007067.
%K A026355 nonn,easy
%O A026355 0,2
%A A026355 _Clark Kimberling_

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