A216155 Numbers n such that floor(sqrt(n + n^3)) = 1 + floor(sqrt(n^3)) = 1 + A000093(n).

2, 13, 40, 43, 46, 52, 109, 152, 190, 243, 336, 351, 356, 366, 422, 584, 592, 741, 937, 978, 1011, 1040, 1137, 1330, 1355, 1362, 1376, 1398, 1434, 2063, 2320, 2520, 2553, 2660, 2665, 2928, 2940, 2993, 3067, 3075, 3092, 3296, 3532, 3631, 3703, 3712, 3730

Offset

1,1

Comments

The sequence is infinite. For values of n not in the sequence we have floor(sqrt(n+n^3)) = floor(sqrt(n^3)) = A000093(n).

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

Mathematica

Select[Range[10000], Floor[Sqrt[# + #^3]] - Floor[Sqrt[#^3]] == 1 &]

Prog

(Haskell)
a216155 n = a216155_list !! (n-1)
a216155_list = filter
   (\x -> a000196 (a034262 x) == a000196 (a000578 x) + 1) [1..]
-- Reinhard Zumkeller, Sep 26 2014

Crossrefs

Cf. A000093 (floor(n^(3/2))).

Cf. A000196, A000578, A034262, A247628 (subsequence).

Sequence in context: A072857 A119535 A210849 * A011919 A323684 A264529

Adjacent sequences: A216152 A216153 A216154 * A216156 A216157 A216158

Keyword

nonn

Author

Zak Seidov, Sep 02 2012

Status

approved