cp's OEIS Frontend

A188917 Where powers of 2 occur in the union of squares and powers of 2.

%I A188917 #23 Oct 02 2024 04:43:52
%S A188917 1,2,3,4,6,8,11,15,20,27,37,51,70,97,135,189,264,371,521,734,1034,
%T A188917 1459,2059,2908,4108,5805,8205,11599,16398,23185,32783,46356,65552,
%U A188917 92698,131089,185381,262162,370746,524307,741475,1048596,1482931,2097173,2965842,4194326,5931664,8388631
%N A188917 Where powers of 2 occur in the union of squares and powers of 2.
%C A188917 A188915(a(n)) = A000079(n); A188915(A188916(n)) = A000290(n).
%H A188917 Robert Israel, <a href="/A188917/b188917.txt">Table of n, a(n) for n = 0..6637</a>
%F A188917 a(n) = floor((n+1)/2) + floor(2^(n/2)). - _Robert Israel_, Jun 13 2019
%p A188917 seq(floor((n+1)/2) + floor(2^(n/2)), n=0..100); # _Robert Israel_, Jun 13 2019
%t A188917 Table[Floor[(n+1)/2] + Floor[2^(n/2)], {n, 0, 50}] (* _Paolo Xausa_, Oct 01 2024 *)
%o A188917 (Haskell)
%o A188917 a188917 n = a188917_list !! n
%o A188917 a188917_list = filter ((== 1) . a209229. a188915) [0..]
%o A188917 -- _Reinhard Zumkeller_, May 19 2015
%o A188917 (Python)
%o A188917 from math import isqrt
%o A188917 def A188917(n): return (n+1>>1)+isqrt(1<<n) # _Chai Wah Wu_, Oct 01 2024
%Y A188917 Cf. A000079, A000290, A017910, A036987.
%Y A188917 Cf. A188915, A188916, A209229, A006127 (subsequence).
%K A188917 nonn,easy
%O A188917 0,2
%A A188917 _Reinhard Zumkeller_, Apr 14 2011