A188916 Where squares occur in the union of squares and powers of 2.

0, 1, 3, 5, 6, 7, 9, 10, 11, 12, 13, 14, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 98, 99, 100

Offset: 0

Author

Reinhard Zumkeller, Apr 14 2011

Keywords

• nonn

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A000079, A000290.

Cf. A188915, A188917, A010052, A006127 (subsequence).

Programs

Haskell

a188916 n = a188916_list !! n
a188916_list = filter ((== 1) . a010052. a188915) [0..]
-- Reinhard Zumkeller, May 19 2015

Mathematica

seq[lim_] := -1 + Position[Union[2^Range[1, Floor[Log2[lim]], 2], Range[0, Floor[Sqrt[lim]]]^2], ?(IntegerQ[Sqrt[#]] &)] // Flatten; seq[10000] (* _Amiram Eldar, Apr 13 2025 *)

Formula

A188915(a(n)) = A000290(n); A188915(A188917(n)) = A000079(n).