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A225126 Central terms of the triangle in A048152. 5
0, 1, 4, 2, 7, 3, 10, 4, 13, 5, 16, 6, 19, 7, 22, 8, 25, 9, 28, 10, 31, 11, 34, 12, 37, 13, 40, 14, 43, 15, 46, 16, 49, 17, 52, 18, 55, 19, 58, 20, 61, 21, 64, 22, 67, 23, 70, 24, 73, 25, 76, 26, 79, 27, 82, 28, 85, 29, 88, 30, 91, 31, 94, 32, 97, 33, 100 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a(n) = A123684(n) for n > 1;

a(n) = A048152(2*n-1,n), central terms;

also a(n) = A060036(2*n-1,n-1) for n > 1.

a(n+1)=the remainder when n^2 is divided by 2n+1. - J. M. Bergot, Jun 25 2013

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (0,2,0,-1).

FORMULA

a(1) = 0, a(2*n) = n and a(2*n+1) = 3*n+1.

a(n) = 2*a(n-2)-a(n-4) for n>5. G.f.: -x^2*(x^3-4*x-1) / ((x-1)^2*(x+1)^2). - Colin Barker, May 01 2013

PROG

(Haskell)

a225126 n = a048152 (2 * n - 1)  n

(PARI) a(n)=n--^2%(2*n+1) \\ Charles R Greathouse IV, Jun 25 2013

CROSSREFS

Sequence in context: A026189 A026213 A319556 * A123684 A180076 A169756

Adjacent sequences:  A225123 A225124 A225125 * A225127 A225128 A225129

KEYWORD

nonn,easy

AUTHOR

Reinhard Zumkeller, Apr 29 2013

STATUS

approved

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Last modified August 5 05:22 EDT 2020. Contains 336209 sequences. (Running on oeis4.)