The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A001027 Powers of 18. (Formerly M5062 N2192) 20
 1, 18, 324, 5832, 104976, 1889568, 34012224, 612220032, 11019960576, 198359290368, 3570467226624, 64268410079232, 1156831381426176, 20822964865671168, 374813367582081024, 6746640616477458432, 121439531096594251776, 2185911559738696531968, 39346408075296537575424, 708235345355337676357632, 12748236216396078174437376 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Same as Pisot sequences E(1, 18), L(1, 18), P(1, 18), T(1, 18). Essentially same as Pisot sequences E(18, 324), L(18, 324), P(18, 324), T(18, 324). See A008776 for definitions of Pisot sequences. The compositions of n in which each natural number is colored by one of p different colors are called p-colored compositions of n. For n>=1, a(n) equals the number of 18-colored compositions of n such that no adjacent parts have the same color. - Milan Janjic, Nov 17 2011 REFERENCES N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS T. D. Noe, Table of n, a(n) for n = 0..100 P. J. Cameron, Sequences realized by oligomorphic permutation groups, J. Integ. Seqs. Vol. 3 (2000), #00.1.5. INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 282 Tanya Khovanova, Recursive Sequences Simon Plouffe, Approximations de séries génératrices et quelques conjectures, Dissertation, Université du Québec à Montréal, 1992; arXiv:0911.4975 [math.NT], 2009. Simon Plouffe, 1031 Generating Functions, Appendix to Thesis, Montreal, 1992 Y. Puri and T. Ward, Arithmetic and growth of periodic orbits, J. Integer Seqs., Vol. 4 (2001), #01.2.1. Index entries for linear recurrences with constant coefficients, signature (18). FORMULA G.f.: 1/(1-18x), e.g.f.: exp(18x). a(n) = 18^n; a(n) = 18*a(n-1) with a(0)=1. - Vincenzo Librandi, Nov 21 2010 MAPLE A001027:=-1/(-1+18*z); # Simon Plouffe in his 1992 dissertation MATHEMATICA Table[18^n, {n, 0, 40}] (* Vladimir Joseph Stephan Orlovsky, Feb 15 2011 *) PROG (Sage) [18**n for n in range(20)] # F. Chapoton, Feb 23 2020 (Sage) [lucas_number1(n, 18, 0) for n in range(1, 17)] # Zerinvary Lajos, Apr 29 2009 (Magma) [ 18^n: n in [0..20] ]; // Vincenzo Librandi, Nov 21 2010 (PARI) a(n)=18^n \\ Charles R Greathouse IV, Sep 28 2015 CROSSREFS Sequence in context: A207498 A285878 A171292 * A285875 A223311 A041145 Adjacent sequences: A001024 A001025 A001026 * A001028 A001029 A001030 KEYWORD nonn,easy AUTHOR N. J. A. Sloane EXTENSIONS More terms from James A. Sellers, Sep 19 2000 STATUS approved

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

Last modified June 19 07:40 EDT 2024. Contains 373492 sequences. (Running on oeis4.)