cp's OEIS Frontend

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.

Showing 1-5 of 5 results.

A079156 Sum of end-to-end Manhattan distances over all self-avoiding n-step walks on cubic lattice. Numerator of mean Manhattan displacement s(n)=a(n)/A078717.

Original entry on oeis.org

10, 67, 396, 2201, 11870, 62571, 324896, 1665349, 8457890, 42605267, 213305636, 1061939193, 5263752278, 25984214383, 127848694424, 627084275649, 3067923454498
Offset: 2

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Author

Hugo Pfoertner, Dec 29 2002

Keywords

Comments

A conjectured asymptotic behavior for the mean Manhattan displacement is shown in a diagram lim n-> infinity a(n)/(A078717(n)*n^nu)=c, for some values of nu near 0.59 at Pfoertner link

Examples

			a(2)=10 because the A078717(2)=5 different self-avoiding 2-step walks end at (1,0,-1),(1,0,1),(1,-1,0),(1,1,0),(2,0,0)->d=2. a(2)=5*2=10. See also "Distribution of end point distance" at Pfoertner link
		

References

Crossrefs

Cf. A001412, A078717, A078605 (corresponding square displacement).

Programs

  • Fortran
    c Program for distance counting available at Pfoertner link.

Formula

a(n)= sum l=1, A078717(n) (|i_l| + |j_l| + |k_l|) where (i_l, j_l, k_l) are the end points of all different self-avoiding n-step walks starting at (0, 0, 0)

A001412 Number of n-step self-avoiding walks on cubic lattice.

Original entry on oeis.org

1, 6, 30, 150, 726, 3534, 16926, 81390, 387966, 1853886, 8809878, 41934150, 198842742, 943974510, 4468911678, 21175146054, 100121875974, 473730252102, 2237723684094, 10576033219614, 49917327838734, 235710090502158, 1111781983442406, 5245988215191414, 24730180885580790, 116618841700433358, 549493796867100942, 2589874864863200574, 12198184788179866902, 57466913094951837030, 270569905525454674614
Offset: 0

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Author

Keywords

References

  • Steven R. Finch, Mathematical Constants, Cambridge, 2003, section 5.10, pp. 331-339.
  • B. D. Hughes, Random Walks and Random Environments, Oxford 1995, vol. 1, p. 462.
  • 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).

Crossrefs

Programs

  • Mathematica
    mo = {{1, 0, 0}, {-1, 0, 0}, {0, 1, 0}, {0, -1, 0}, {0, 0, 1}, {0, 0, -1}}; a[0] = 1;
    a[tg_, p_: {{0, 0, 0}}] := Block[{e, mv = Complement[Last[p] + # & /@ mo, p]},
    If[tg == 1, Return[Length@mv],Sum[a[tg - 1, Append[p, e]], {e, mv}]]];
    a /@ Range[0, 8]
    (* Robert FERREOL, Nov 30 2018, after the program of Giovanni Resta in A001411 *)
  • Python
    def add(L,x):
        M=[y for y in L];M.append(x)
        return(M)
    plus=lambda L,M : [x+y for x,y in zip(L,M)]
    mo=[[1,0,0],[-1,0,0],[0,1,0],[0,-1,0],[0,0,1],[0,0,-1]]
    def a(n,P=[[0,0,0]]):
        if n==0: return(1)
        mv1 = [plus(P[-1],x) for x in mo]
        mv2=[x for x in mv1 if x not in P]
        if n==1: return(len(mv2))
        else: return(sum(a(n-1,add(P,x)) for x in mv2))
    [a(n) for n in range(8)]
    # Robert FERREOL, Nov 30 2018

A002902 Number of n-step self-avoiding walks on a cubic lattice with a first step along the positive x, y, or z axis.

Original entry on oeis.org

3, 15, 75, 363, 1767, 8463, 40695, 193983, 926943, 4404939, 20967075, 99421371, 471987255, 2234455839, 10587573027, 50060937987, 236865126051, 1118861842047, 5288016609807, 24958663919367, 117855045251079, 555890991721203, 2622994107595707
Offset: 1

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Author

Keywords

References

  • B. D. Hughes, Random Walks and Random Environments, Oxford 1995, vol. 1, p. 462.
  • 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).

Crossrefs

Equals (1/2)*A001412. Cf. A078717, A001411, A001413.

Extensions

Name amended by Scott R. Shannon, Sep 17 2020

A078605 Sum of square displacements over all self-avoiding n-step walks on the cubic lattice with the first step specified. Numerator of mean square displacement s(n)=a(n)/(A001412(n)/6).

Original entry on oeis.org

1, 12, 97, 672, 4261, 25588, 147821, 830576, 4566917, 24692980, 131682825, 694386864, 3626770709, 18790632772, 96675376705, 494382431552, 2514666026897, 12730690730212, 64177763220925, 322314275563424, 1613192327878789, 8049191357609204, 40048773875769449, 198750753713937600
Offset: 1

Views

Author

Hugo Pfoertner, Dec 09 2002

Keywords

Comments

A comparison with the conjectured asymptotic behavior of the mean square displacement s(n) over all n-step self-avoiding walks given in Weisstein's article is shown in "Asymptotic Behavior of Mean Square Displacement" at the Pfoertner link.

Examples

			a(2)=12 because the A001412(2)/6 = 5 different self-avoiding 2-step walks end at (1,0,-1), (1,0,1), (1,-1,0), (1,1,0)->d^2=2 and at (2,0,0)->d^2=4. a(2) = 4*2 + 1*4 = 12. See also "Distribution of end point distance" at first link.
		

References

Crossrefs

Cf. A001412, A078717, A079156 (corresponding Manhattan distance sum).
Equals A118313/6.

Programs

  • Fortran
    c Program for distance counting available at Pfoertner link.

Formula

a(n) = Sum_{L=1..A001412(n)/6} ( i_L^2 + j_L^2 + k_L^2 ) where (i_L, j_L, k_L) are the endpoints of all different self-avoiding n-step walks.

Extensions

Terms a(19)-a(36) taken from A118313 by Hugo Pfoertner, Aug 20 2014
Name amended by Scott R. Shannon, Sep 17 2020

A140476 Number of self-avoiding walks on cubic lattice with no more than n steps.

Original entry on oeis.org

1, 7, 37, 187, 913, 4447, 21373, 102763, 490729, 2344615, 11154493, 53088643, 251931385, 1195905895, 5664817573, 26839963627, 126961839601, 600692091703, 2838415775797, 13414448995411, 63331776834145, 299041867336303
Offset: 0

Views

Author

Jonathan Vos Post, Jun 29 2008

Keywords

Comments

Primes include a(1) = 7, a(2) = 37, a(5) = 4447, a(8) = 102763, a(15) = 26839963627.

Examples

			a(9) = 1 + 6 + 30 + 150 + 726 + 3534 + 16926 + 81390 + 387966 + 1853886 = 2344615.
		

Crossrefs

Partial sums of A001412.
Showing 1-5 of 5 results.