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 1-4 of 4 results.

A126500 Number of base 32 n-digit numbers with adjacent digits differing by three or less.

Original entry on oeis.org

1, 32, 212, 1428, 9676, 65800, 448524, 3062596, 20939104, 143307908, 981612296, 6728277248, 46143758054, 316613006372, 2173302900418, 14923204166476, 102502175850752, 704231575697316, 4839430076086740, 33262613275263868
Offset: 0

Views

Author

R. H. Hardin, Dec 27 2006

Keywords

Comments

[Empirical] a(base,n)=a(base-1,n)+7^(n-1) for base>=3n-2; a(base,n)=a(base-1,n)+7^(n-1)-2 when base=3n-3

Crossrefs

Cf. Base 32 differing by two or less A126419, one or less A126386.

A285266 Array read by antidiagonals: T(m,n) = number of m-ary words of length n with adjacent elements differing by 2 or less.

Original entry on oeis.org

1, 3, 1, 9, 4, 1, 27, 14, 5, 1, 81, 50, 19, 6, 1, 243, 178, 75, 24, 7, 1, 729, 634, 295, 100, 29, 8, 1, 2187, 2258, 1161, 418, 125, 34, 9, 1, 6561, 8042, 4569, 1748, 543, 150, 39, 10, 1, 19683, 28642, 17981, 7310, 2363, 668, 175, 44, 11, 1
Offset: 3

Views

Author

Andrew Howroyd, Apr 15 2017

Keywords

Comments

All rows are linear recurrences with constant coefficients. See PARI script to obtain generating functions.

Examples

			Array starts (m>=3, n>=0):
1  3  9  27  81  243   729  2187   6561 ...
1  4 14  50 178  634  2258  8042  28642 ...
1  5 19  75 295 1161  4569 17981  70763 ...
1  6 24 100 418 1748  7310 30570 127842 ...
1  7 29 125 543 2363 10287 44787 194995 ...
1  8 34 150 668 2986 13362 59816 267802 ...
1  9 39 175 793 3611 16475 75229 343633 ...
1 10 44 200 918 4236 19598 90790 420870 ...
		

Crossrefs

Rows 4-32 are A055099, A126392-A126419.

Programs

  • Mathematica
    diff = 2; m0 = 3; mmax = 12;
    TransferGf[m_, u_, t_, v_, z_] := Array[u, m].LinearSolve[IdentityMatrix[m] - z*Array[t, {m, m}], Array[v, m]]
    RowGf[d_, m_, z_] := 1+z*TransferGf[m, 1&, Boole[Abs[#1-#2] <= d]&, 1&, z];
    row[m_] := row[m] = CoefficientList[RowGf[diff, m, x] + O[x]^mmax, x];
    T[m_ /; m >= m0, n_ /; n >= 0] := row[m][[n + 1]];
    Table[T[m - n , n], {m, m0, mmax}, {n, m - m0, 0, -1}] // Flatten (* Jean-François Alcover, Jun 17 2017, adapted from PARI *)
  • PARI
    TransferGf(m,u,t,v,z)=vector(m,i,u(i))*matsolve(matid(m)-z*matrix(m,m,i,j,t(i,j)),vectorv(m,i,v(i)));
    RowGf(d,m,z)=1+z*TransferGf(m, i->1, (i,j)->abs(i-j)<=d, j->1, z);
    for(m=3, 10, print(RowGf(2,m,x)));
    for(m=3, 10, v=Vec(RowGf(2,m,x) + O(x^9)); for(n=1, length(v), print1( v[n], ", ") ); print(); );

A126527 Number of base 32 n-digit numbers with adjacent digits differing by four or less.

Original entry on oeis.org

1, 32, 268, 2292, 19748, 170904, 1483284, 12899556, 112350184, 979640156, 8549531716, 74665238648, 652426700120, 5703387501520, 49875030912772, 436266613941484, 3816936851122500, 33400491065984904, 292314430831005104
Offset: 0

Views

Author

R. H. Hardin, Dec 28 2006

Keywords

Comments

[Empirical] a(base,n)=a(base-1,n)+9^(n-1) for base>=4n-3; a(base,n)=a(base-1,n)+9^(n-1)-2 when base=4n-4

Crossrefs

Cf. Base 32 differing by three or less A126500, two or less A126419, one or less A126386.

A126553 Number of base 32 n-digit numbers with adjacent digits differing by five or less.

Original entry on oeis.org

1, 32, 322, 3322, 34572, 361614, 3794396, 39900036, 420199296, 4429943806, 46737838878, 493369276732, 5210044608364, 55033710005144, 581433527148552, 6143714493591276, 64923869760680486, 686132382682831498
Offset: 0

Views

Author

R. H. Hardin, Dec 28 2006

Keywords

Comments

[Empirical] a(base,n)=a(base-1,n)+11^(n-1) for base>=5n-4; a(base,n)=a(base-1,n)+11^(n-1)-2 when base=5n-5

Crossrefs

Cf. Base 32 differing by four or less A126527, three or less A126500, two or less A126419, one or less A126386.
Showing 1-4 of 4 results.