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A188917
Where powers of 2 occur in the union of squares and powers of 2.
4
1, 2, 3, 4, 6, 8, 11, 15, 20, 27, 37, 51, 70, 97, 135, 189, 264, 371, 521, 734, 1034, 1459, 2059, 2908, 4108, 5805, 8205, 11599, 16398, 23185, 32783, 46356, 65552, 92698, 131089, 185381, 262162, 370746, 524307, 741475, 1048596, 1482931, 2097173, 2965842, 4194326, 5931664, 8388631
OFFSET
0,2
COMMENTS
A188915(a(n)) = A000079(n); A188915(A188916(n)) = A000290(n).
LINKS
FORMULA
a(n) = floor((n+1)/2) + floor(2^(n/2)). - Robert Israel, Jun 13 2019
MAPLE
seq(floor((n+1)/2) + floor(2^(n/2)), n=0..100); # Robert Israel, Jun 13 2019
MATHEMATICA
Table[Floor[(n+1)/2] + Floor[2^(n/2)], {n, 0, 50}] (* Paolo Xausa, Oct 01 2024 *)
PROG
(Haskell)
a188917 n = a188917_list !! n
a188917_list = filter ((== 1) . a209229. a188915) [0..]
-- Reinhard Zumkeller, May 19 2015
(Python)
from math import isqrt
def A188917(n): return (n+1>>1)+isqrt(1<<n) # Chai Wah Wu, Oct 01 2024
CROSSREFS
Cf. A188915, A188916, A209229, A006127 (subsequence).
Sequence in context: A023434 A353035 A087192 * A046935 A241334 A374760
KEYWORD
nonn,easy
AUTHOR
Reinhard Zumkeller, Apr 14 2011
STATUS
approved