A164386 Numbers which are not 1 larger than a nonzero square.

1, 3, 4, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80

Offset

1,2

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Formula

{1} U {A000027 \ A002522} (complement of A002522).

a(n) = n + floor(sqrt(n-1) + 1/2).

Example

For n = 26, a(26) = n + [sqrt(n-1) + 1/2] = 26 + [sqrt(26-1) + 1/2] = 26 + [5.5] = 31.

Mathematica

With[{nn=100}, Complement[Range[nn], Range[Floor[Sqrt[nn]]]^2+1]] (* Harvey P. Dale, Sep 06 2022 *)

Prog

(PARI) is(n)=!issquare(n-1) || n==1 \\ Charles R Greathouse IV, Sep 01 2015

Crossrefs

Sequence in context: A085925 A107907 A080804 * A111909 A184010 A256827

Adjacent sequences: A164383 A164384 A164385 * A164387 A164388 A164389

Keyword

nonn,easy

Author

Jaroslav Krizek, Aug 14 2009

Extensions

Edited by R. J. Mathar, Aug 20 2009

Corrected by Jaroslav Krizek, Oct 24 2009

Status

approved