OFFSET
1,2
COMMENTS
a(5)=2649601*(2*a(1)+1)-1-a(4), a(6)=2649601*(2*a(2)+1)-1-a(3), a(7)=2649601*(2*a(3)+1)-1-a(2), a(8)=2649601*(2*a(4)+1)-1-a(1), a(9)=2649601*(2*a(5)+1)-1-a(1), a(10)=2649601*(2*a(6)+1)-1-a(2), a(11)=2649601*(2*a(7)+1)-1-a(3), a(12)=2649601*(2*a(8)+1)-1-a(4), a(13)=2649601*(2*a(9)+1)-1-a(1), a(14)=2649601*(2*a(10)+1)-1-a(1). This is a strange recurrence - does it continue ? Remark : 2649601 = 23*24*25*192+1
In terms of indices of triangular numbers: A000217(n) = 4*A000217[(j-1)/2]/23. - R. J. Mathar, Dec 05 2007
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..595
Index entries for linear recurrences with constant coefficients, signature (1,2302,-2302,-1,1).
FORMULA
Union of two sequences defined by the recurrence a(n+1)=2302*a(n)-a(n-1)+1150 a(0)=0, a(1)=335, a(2)=772320, ... a(0)=0, a(1)=815, a(2)=1877280, ... - Max Alekseyev, Apr 09 2005
O.g.f.: -5*(67*x^2+96*x+67)*x^2/((x^2+48*x+1)*(x^2-48*x+1)*(-1+x)). - R. J. Mathar, Dec 05 2007
MATHEMATICA
LinearRecurrence[{1, 2302, -2302, -1, 1}, {0, 335, 815, 772320, 1877280}, 20] (* Harvey P. Dale, May 20 2021 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Pierre CAMI, Apr 07 2005
EXTENSIONS
More terms from Max Alekseyev, Apr 09 2005
More terms from R. J. Mathar, Dec 05 2007
STATUS
approved