The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A074058 Reflected tetranacci numbers A073817. 8
 4, -1, -1, -1, 7, -6, -1, -1, 15, -19, 4, -1, 31, -53, 27, -6, 63, -137, 107, -39, 132, -337, 351, -185, 303, -806, 1039, -721, 791, -1915, 2884, -2481, 2303, -4621, 7683, -7846, 7087, -11545, 19987, -23375, 22020, -30177, 51519, -66737, 67415, -82374, 133215, -184993, 201567, -232163, 348804 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS These numbers are obtained taking as characteristic polynomial the reflected ch.p. of the tetranacci generalized sequence and imposing initial conditions such that the coefficients of the generalized Binet's formula for the two sequences are the same. Also a(n) is the trace of A^(-n), where A is the tetramatrix ((1,1,0,0), (1,0,1,0),(1,0,0,1),(1,0,0,0)). REFERENCES R. L. Graham, D. E. Knuth and O. Patashnik, "Concrete Mathematics", Addison-Wesley, Reading, MA, 1998. LINKS Indranil Ghosh, Table of n, a(n) for n = 0..8998 FORMULA a(n) = -a(n-1)-a(n-2)-a(n-3)+a(n-4), a(0)=4, a(1)=-1, a(2)=-1, a(3)=-1. G.f.: (4+3x+2x^2+x^3)/(1+x+x^2+x^3-x^4). MATHEMATICA CoefficientList[Series[(4+3*x+2*x^2+x^3)/(1+x+x^2+x^3-x^4), {x, 0, 1}], x] CROSSREFS Cf. A073817. Sequence in context: A182665 A131299 A073937 * A308552 A088440 A300253 Adjacent sequences:  A074055 A074056 A074057 * A074059 A074060 A074061 KEYWORD easy,sign AUTHOR Mario Catalani (mario.catalani(AT)unito.it), Aug 16 2002 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 30 11:52 EDT 2020. Contains 334724 sequences. (Running on oeis4.)