

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*n1,n), central terms;
also a(n) = A060036(2*n1,n1) 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(n2)a(n4) for n>5. G.f.: x^2*(x^34*x1) / ((x1)^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



