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A184985 Nonnegative integers excluding 2. 3
0, 1, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Number of adjacent pairs of sectors in a circle with n equal sections.

LINKS

Table of n, a(n) for n=1..70.

Index entries for linear recurrences with constant coefficients, signature (2,-1).

FORMULA

G.f.: (1+x-x^2)*x^2/(1-x)^2. - Philippe Deléham, Dec 23 2011

a(1) = 0, a(2) = 1, a(n) = n for n > 2. - Wesley Ivan Hurt, Jun 17 2019

MAPLE

A184985:=n->piecewise(n<3, n-1, n); seq(A184985(n), n=1..100);

MATHEMATICA

CoefficientList[Series[(1+x-x^2)*x^2/(1-x)^2, {x, 0, 50}], x] (* G. C. Greubel, Jun 03 2017 *)

PROG

(PARI) a(n)=n-(n<3) \\ Charles R Greathouse IV, Dec 22 2011

CROSSREFS

Cf. A000027.

Sequence in context: A030544 A141213 A171950 * A114637 A009056 A065475

Adjacent sequences:  A184982 A184983 A184984 * A184986 A184987 A184988

KEYWORD

nonn,easy

AUTHOR

Wesley Ivan Hurt, Dec 22 2011

STATUS

approved

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Last modified October 16 05:41 EDT 2021. Contains 348035 sequences. (Running on oeis4.)