A047839 a(n) = n + floor( sqrt(2*n) ).

2, 4, 5, 6, 8, 9, 10, 12, 13, 14, 15, 16, 18, 19, 20, 21, 22, 24, 25, 26, 27, 28, 29, 30, 32, 33, 34, 35, 36, 37, 38, 40, 41, 42, 43, 44, 45, 46, 47, 48, 50, 51, 52, 53, 54, 55, 56, 57, 58, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 72, 73, 74, 75, 76, 77, 78, 79

Offset

1,1

Comments

Complement of A047838.

Links

G. C. Greubel, Table of n, a(n) for n = 1..10000

Mathematica

Table[n +Floor[Sqrt[2*n]], {n, 1, 100}] (* G. C. Greubel, Sep 08 2018 *)

Prog

(PARI) {a(n) = if( n<0, 0, n + sqrtint(2*n))}
(Magma) [n +Floor(Sqrt(2*n)): n in [1..100]]; // G. C. Greubel, Sep 08 2018

Crossrefs

Cf. A047838.

Sequence in context: A355890 A145395 A049692 * A285601 A139255 A277676

Adjacent sequences: A047836 A047837 A047838 * A047840 A047841 A047842

Keyword

nonn,easy

Author

Michael Somos, May 07 1999

Status

approved