This site is supported by donations to The OEIS Foundation.

 Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS". Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A016153 (9^n-4^n)/5. 9
 0, 1, 13, 133, 1261, 11605, 105469, 953317, 8596237, 77431669, 697147165, 6275373061, 56482551853, 508359743893, 4575304803901, 41178011670565, 370603178776909, 3335432903959477, 30018913315504477, 270170288559017029 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS a(n) is also the coefficient of x^(n-1) in the bivariate Fibonacci polynomials F(n)(x,y)=xF(n-1)(x,y)+yF(n-2)(x,y),F(0)(x,y)=0,F(1)(x,y)=1, when we write 13x for x and -36x^2 for y. - Mario Catalani (mario.catalani(AT)unito.it), Dec 09 2002 LINKS R. Flórez, R. A. Higuita, A. Mukherjee, Alternating Sums in the Hosoya Polynomial Triangle, Article 14.9.5 Journal of Integer Sequences, Vol. 17 (2014). Index entries for linear recurrences with constant coefficients, signature (13, -36). FORMULA G.f.: x/((1-4*x)*(1-9*x)). a(n)=13*a(n-1)-36*a(n-2). a(n) = A015441(2*n). MATHEMATICA Join[{a=0, b=1}, Table[c=13*b-36*a; a=b; b=c, {n, 60}]](*and/or*)f[n_]:=(9^n-4^n)/5; f[Range[0, 60]] (* Vladimir Joseph Stephan Orlovsky, Feb 01 2011 *) PROG (PARI) a(n)=(9^n-4^n)/5 CROSSREFS Cf. A015441. Sequence in context: A199144 A198664 A081042 * A187732 A031138 A097166 Adjacent sequences:  A016150 A016151 A016152 * A016154 A016155 A016156 KEYWORD nonn AUTHOR 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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.