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 1-3 of 3 results.

A073031 Number of ways of making change for n cents using coins of sizes 1, 2, 5, 10 cents, when order matters.

Original entry on oeis.org

1, 1, 2, 3, 5, 9, 15, 26, 44, 75, 129, 220, 377, 644, 1101, 1883, 3219, 5505, 9412, 16093, 27517, 47049, 80448, 137553, 235195, 402148, 687611, 1175712, 2010288, 3437288, 5877241, 10049189, 17182590, 29379620, 50234693, 85893702
Offset: 0

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Author

Miklos Kristof, Aug 22 2002

Keywords

Examples

			a(4)=5 because 4 = 1 + 1 + 1 + 1 = 1 + 1 + 2 = 1 + 2 + 1 = 2 + 1 + 1 = 2 + 2: five possible exchange. a(15) = a(14) + a(13) + a(10) + a(5) = 1883 = 1101 + 644 + 129 + 9.
		

References

  • Peter Boros (borospet(AT)freemail.hu): Lectures on Fibonacci's World at the SOTERIA Foundation, 1999.
  • P. Henrici, Applied and Computational Complex Analysis. Wiley, NY, 3 vols., 1974-1986. (Vol. 1, p. 580.)

Crossrefs

Cf. A079971.

Programs

  • Maple
    a:= n-> (Matrix(10, (i,j)-> if i+1=j or j=1 and member (i,[1, 2, 5, 10]) then 1 else 0 fi)^n)[1, 1]: seq(a(n), n=0..35); # Alois P. Heinz, Oct 07 2008
  • Mathematica
    LinearRecurrence[{1, 1, 0, 0, 1, 0, 0, 0, 0, 1}, {1, 1, 2, 3, 5, 9, 15, 26, 44, 75}, 36] (* Jean-François Alcover, Jan 25 2025 *)

Formula

a(n) = a(n-1) + a(n-2) + a(n-5) + a(n-10), a(0)=1.
G.f.: 1/(1 - x - x^2 - x^5 - x^10). - Franklin T. Adams-Watters, Oct 24 2006
With offset 1, the INVERT transform of (1 + x + x^4 + x^9). - Gary W. Adamson, Apr 04 2017

A246690 Number A(n,k) of compositions of n into parts of the k-th list of distinct parts in the order given by A246688; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 0, 1, 0, 2, 0, 1, 0, 1, 1, 0, 3, 1, 1, 0, 1, 0, 1, 1, 5, 0, 1, 0, 1, 1, 0, 2, 0, 8, 1, 1, 0, 1, 0, 1, 0, 3, 0, 13, 0, 1, 0, 1, 0, 1, 1, 1, 4, 1, 21, 1, 1, 0, 1, 1, 0, 1, 2, 0, 6, 0, 34, 0, 1, 0, 1, 1, 2, 0, 1, 3, 0, 9, 0, 55, 1, 1, 0
Offset: 0

Views

Author

Alois P. Heinz, Sep 01 2014

Keywords

Comments

The first lists of distinct parts in the order given by A246688 are: 0:[], 1:[1], 2:[2], 3:[1,2], 4:[3], 5:[1,3], 6:[4], 7:[1,4], 8:[2,3], 9:[5], 10:[1,2,3], 11:[1,5], 12:[2,4], 13:[6], 14:[1,2,4], 15:[1,6], 16:[2,5], 17:[3,4], 18:[7], 19:[1,2,5], 20:[1,3,4], ... .

Examples

			Square array A(n,k) begins:
  1, 1, 1,  1, 1,  1, 1,  1, 1, 1,   1, 1, 1, 1,   1, ...
  0, 1, 0,  1, 0,  1, 0,  1, 0, 0,   1, 1, 0, 0,   1, ...
  0, 1, 1,  2, 0,  1, 0,  1, 1, 0,   2, 1, 1, 0,   2, ...
  0, 1, 0,  3, 1,  2, 0,  1, 1, 0,   4, 1, 0, 0,   3, ...
  0, 1, 1,  5, 0,  3, 1,  2, 1, 0,   7, 1, 2, 0,   6, ...
  0, 1, 0,  8, 0,  4, 0,  3, 2, 1,  13, 2, 0, 0,  10, ...
  0, 1, 1, 13, 1,  6, 0,  4, 2, 0,  24, 3, 3, 1,  18, ...
  0, 1, 0, 21, 0,  9, 0,  5, 3, 0,  44, 4, 0, 0,  31, ...
  0, 1, 1, 34, 0, 13, 1,  7, 4, 0,  81, 5, 5, 0,  55, ...
  0, 1, 0, 55, 1, 19, 0, 10, 5, 0, 149, 6, 0, 0,  96, ...
  0, 1, 1, 89, 0, 28, 0, 14, 7, 1, 274, 8, 8, 0, 169, ...
		

Crossrefs

Main diagonal gives A246691.
Cf. A246688, A246720 (the same for partitions).

Programs

  • Maple
    b:= proc(n, i) b(n, i):= `if`(n=0, [[]], `if`(i>n, [],
          [map(x->[i, x[]], b(n-i, i+1))[], b(n, i+1)[]]))
        end:
    f:= proc() local i, l; i, l:=0, [];
          proc(n) while n>=nops(l)
            do l:=[l[], b(i, 1)[]]; i:=i+1 od; l[n+1]
          end
        end():
    g:= proc(n, l) option remember; `if`(n=0, 1,
          add(`if`(i>n, 0, g(n-i, l)), i=l))
        end:
    A:= (n, k)-> g(n, f(k)):
    seq(seq(A(n, d-n), n=0..d), d=0..14);
  • Mathematica
    b[n_, i_] := b[n, i] = If[n == 0, {{}}, If[i>n, {}, Join[Prepend[#, i]& /@ b[n - i, i + 1], b[n, i + 1]]]];
    f = Module[{i = 0, l = {}}, Function[n, While[n >= Length[l], l = Join[l, b[i, 1]]; i++]; l[[n + 1]]]];
    g[n_, l_] := g[n, l] = If[n==0, 1, Sum[If[i>n, 0, g[n - i, l]], {i, l}]];
    A[n_, k_] := g[n, f[k]];
    Table[Table[A[n, d - n], {n, 0, d}], {d, 0, 14}] // Flatten (* Jean-François Alcover, Dec 07 2020, after Alois P. Heinz *)

A245367 Compositions of n into parts 3, 5 and 7.

Original entry on oeis.org

1, 0, 0, 1, 0, 1, 1, 1, 2, 1, 3, 3, 3, 6, 5, 8, 10, 11, 17, 18, 25, 32, 37, 52, 61, 79, 102, 123, 163, 200, 254, 326, 402, 519, 649, 819, 1045, 1305, 1664, 2096, 2643, 3358, 4220, 5352, 6759, 8527, 10806, 13622, 17237, 21785, 27501, 34802, 43934, 55544, 70209, 88672, 112131, 141644, 179018, 226274, 285860, 361358
Offset: 0

Views

Author

David Neil McGrath, Aug 20 2014

Keywords

Examples

			a(16) = 10: the compositions are the permutations of [5533] (there are 4!/2!2!=6 of them) and the permutations of [7333] (there are 4!/3!=4).
		

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{0,0,1,0,1,0,1},{1,0,0,1,0,1,1},70] (* Harvey P. Dale, Jan 27 2017 *)
  • PARI
    Vec(1/(1-x^3-x^5-x^7) +O(x^66)) \\ Joerg Arndt, Aug 20 2014

Formula

G.f: 1/(1-x^3-x^5-x^7).
a(n) = a(n-3) + a(n-5) + a(n-7).
Showing 1-3 of 3 results.