login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A085151
Numbers generated by the Fibonacci polynomial x^4 + 3x^2 + 1.
2
5, 29, 109, 305, 701, 1405, 2549, 4289, 6805, 10301, 15005, 21169, 29069, 39005, 51301, 66305, 84389, 105949, 131405, 161201, 195805, 235709, 281429, 333505, 392501, 459005, 533629, 617009, 709805, 812701, 926405, 1051649, 1189189
OFFSET
1,1
COMMENTS
Start with the Fibonacci polynomials of A011973 (see "examples") and put in appropriate exponents, e.g. {1,1} = x^2 + 1, the generator of A002522; {1,2} = x^3 + 2x, the generator of A054602; and to get the next polynomial, multiply by x and add the previous polynomial, such that the generator for A085151 = x^4 + 3x^2 + 1 = (x)(x^3+2x) + (x^2+1).
FORMULA
1. x^4 + 3x^2 + 1 2. a(n) = n*A054602(n) + A002522(n) 3. a(n) = denominator of [n, n, n, n]; with numerator = A054602(n).
a(n)=A057721(n). [From R. J. Mathar, Sep 12 2008]
EXAMPLE
1. a(2) = f(2) of x^4 + 3x^2 + 1 = 29
2. a(2) = 29 = (2)A054602 + A002522(2) = (2)(12) + 5.
3. [2,2,2,2] = 12/29; a(2) = 29, & 12 = A054602(2). Thus [n,n,n,n] = A054602(n)/A085151(n).
MATHEMATICA
f[n_] := n^4 + 3n^2 + 1; Array[f, 33]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gary W. Adamson, Jun 21 2003
EXTENSIONS
More terms from Robert G. Wilson v, Aug 06 2006
STATUS
approved