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A155450 Numbers equal to 5 or 18 mod 23. 6
5, 18, 28, 41, 51, 64, 74, 87, 97, 110, 120, 133, 143, 156, 166, 179, 189, 202, 212, 225, 235, 248, 258, 271, 281, 294, 304, 317, 327, 340, 350, 363, 373, 386, 396, 409, 419, 432, 442, 455, 465, 478, 488, 501, 511, 524, 534, 547, 557, 570, 580, 593, 603, 616 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Or, numbers n such that n^2 == 2 mod 23.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (1,1,-1).

FORMULA

a(n) = a(n-1)+a(n-2)-a(n-3), with a(1)=5, a(2)=18, a(3)=28.

a(n) = (1/4)*(23-3*(-1)^(n-1)+46*(n-1)). - Paolo P. Lava, Jan 26 2009

G.f.: x*(5 + 13*x + 5*x^2)/((1 + x)*(1 - x)^2). - Vincenzo Librandi, May 03 2014

MATHEMATICA

LinearRecurrence[{1, 1, -1}, {5, 18, 28}, 80] (* Vincenzo Librandi, Feb 29 2012 *)

CoefficientList[Series[(5 + 13 x + 5 x^2)/((1 + x) (1 - x)^2), {x, 0, 60}], x] (* Vincenzo Librandi, May 03 2014 *)

CROSSREFS

Sequence in context: A055371 A034098 A034108 * A322409 A287894 A140365

Adjacent sequences:  A155447 A155448 A155449 * A155451 A155452 A155453

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Jan 22 2009

EXTENSIONS

New name from Charles R Greathouse IV, Jan 11 2012

STATUS

approved

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Last modified August 3 07:58 EDT 2021. Contains 346435 sequences. (Running on oeis4.)