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This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

User: Jos Koot

Jos Koot's wiki page.

Jos Koot has authored 1 sequences.

A125295 Number of different non-self-crossing ways of moving a tower of Hanoi from one peg onto another peg.

Original entry on oeis.org

1, 2, 12, 1872, 6563711232, 282779810171805015122254036992, 22612323802416302740572466532905158028496454353087246911545156210129751385945830223511552
Offset: 0

Author

Jos Koot, Dec 08 2006

Keywords

Comments

In other words, a sequence of moves starting with all disks on the starting peg, ending with all disks on the destination peg and never more than once producing the same distribution of disks among the pegs (assuming 3 pegs).

Programs

  • Maple
    f:= proc(n) option remember; if n = 0 then 1 else f(n-1)^2*(f(n-1)+1); fi; end; seq(f(n), n=0..7);
  • Mathematica
    t={1,2};Do[AppendTo[t,t[[-1]]^3+t[[-1]]^2],{n,6}];t (* Vladimir Joseph Stephan Orlovsky, Feb 02 2012 *)
    RecurrenceTable[{a[n+1] == a[n]^2 * (a[n]+1), a[0]==1}, a, {n, 0, 7}] (* Vaclav Kotesovec, Mar 11 2016 *)
  • Scheme
    (define (next n) (* n n (+ n 1)))
    (define (list-elements nr-of-elements n0 next)
      (let list-elements ((i 0) (n n0))
        (show i n)
        (let ((i (add1 i)))
          (if (< i nr-of-elements) (list-elements i (next n))))))
    (define (show i n) (printf "N(~a)=~a~n~n" i n))
    (list-elements 6 1 next)

Formula

a(n+1) = (a(n)^2)*(a(n)+1).
a(n) ~ c^(3^n), where c = 1.321902354497090972160055360813404141485787154023407081... . Vaclav Kotesovec, Mar 11 2016

Extensions

Checked by N. J. A. Sloane, Feb 10 2007. The next term is too large to include.