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A164386 Numbers which are not 1 larger than a nonzero square. 2
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified December 5 02:23 EST 2022. Contains 358572 sequences. (Running on oeis4.)