A212190 Squares that are the sum of exactly three distinct powers of 2.

25, 49, 81, 100, 196, 289, 324, 400, 529, 784, 1089, 1156, 1296, 1600, 2116, 3136, 4225, 4356, 4624, 5184, 6400, 8464, 12544, 16641, 16900, 17424, 18496, 20736, 25600, 33856, 50176, 66049, 66564, 67600, 69696, 73984, 82944, 102400, 135424, 200704, 263169

Offset

1,1

Comments

Squares with exactly three ones in their binary representation: A000120(a(n)) = 3;

squares in A014311;

a(n) = A212191(n)^2.

Links

Giovanni Resta, Table of n, a(n) for n = 1..10000 (first 1000 terms from Reinhard Zumkeller)

Mathematica

Select[Range[1000]^2, DigitCount[#, 2, 1] == 3&] (* Jean-François Alcover, Nov 07 2016 *)

Prog

(Haskell)
a212190 n = a212190_list !! (n-1)
a212190_list = filter ((== 1) . a010052) a014311_list

Crossrefs

Cf. A010052, A212192.

Sequence in context: A377884 A068874 A018936 * A324871 A241836 A110484

Adjacent sequences: A212187 A212188 A212189 * A212191 A212192 A212193

Keyword

nonn

Author

Reinhard Zumkeller, May 03 2012

Status

approved