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.

Previous Showing 11-13 of 13 results.

A332690 Sum of all numbers in bijective base-9 numeration with digit sum n.

Original entry on oeis.org

0, 1, 12, 124, 1248, 12496, 124992, 1249984, 12499968, 124999936, 1249999862, 12499999623, 124999998144, 1249999984364, 12499999840480, 124999998308464, 1249999981991936, 12499999808733888, 124999997974967808, 1249999978624935680, 12499999774999871588
Offset: 0

Views

Author

Alois P. Heinz, Feb 19 2020

Keywords

Comments

Different from A016134.

Examples

			a(2) = 12 = 2 + 10 = 2_bij9 + 11_bij9.
		

Crossrefs

Programs

  • Maple
    b:= proc(n) option remember; `if`(n=0, [1, 0], add((p->
          [p[1], p[2]*9+p[1]*d])(b(n-d)), d=1..min(n, 9)))
        end:
    a:= n-> b(n)[2]:
    seq(a(n), n=0..23);

Formula

G.f.: (Sum_{j=1..9} j*x^j) / ((B(x) - 1) * (9*B(x) - 1)) with B(x) = Sum_{j=1..9} x^j.
a(n) = A028904(A332691(n)).
a(n) = A016134(n-1) for n = 1..9.

A332691 Bijective base-9 representation of the sum of all numbers in bijective base-9 numeration with digit sum n.

Original entry on oeis.org

1, 13, 147, 1636, 18124, 199399, 2314581, 25461653, 281178597, 3192976395, 35233852789, 387573484456, 4374418444135, 48228613881184, 541525753635894, 5956784387951128, 66635738355523786, 743994232656361639, 8285146556418623572, 92246623188575957748
Offset: 1

Views

Author

Alois P. Heinz, Feb 19 2020

Keywords

Examples

			a(2) = 13_bij9 = 12 = 2 + 10 = 2_bij9 + 11_bij9.
		

Crossrefs

Programs

  • Maple
    b:= proc(n) option remember; `if`(n=0, [1, 0], add((p->
          [p[1], p[2]*9+p[1]*d])(b(n-d)), d=1..min(n, 9)))
        end:
    g:= proc(n) local d, l, m; m, l:= n, "";
          while m>0 do d:= irem(m, 9, 'm');
            if d=0 then d:=9; m:= m-1 fi; l:= d, l
          od; parse(cat(l))
        end:
    a:= n-> g(b(n)[2]):
    seq(a(n), n=1..23);

Formula

a(n) = A052382(A332690(n)).

A332711 Sum of all numbers in bijective base-n numeration with digit sum n.

Original entry on oeis.org

0, 1, 5, 28, 203, 1936, 23517, 349504, 6149495, 124999936, 2881935953, 74300836864, 2118007738035, 66142897770496, 2245609694259557, 82351536043343872, 3244079458377786863, 136619472483668525056, 6125138252818308310041, 291271111111111111081984
Offset: 0

Views

Author

Alois P. Heinz, Feb 20 2020

Keywords

Comments

The number of numbers in bijective base-n numeration with digit sum n equals the number of compositions of n: A000079(n).

Examples

			a(0) =  0.
a(1) =  1 = 1_bij1.
a(2) =  5 = 3 + 2 = 11_bij2 + 2_bij2.
a(3) = 28 = 13 + 7 + 5 + 3 = 111_bij3 + 21_bij3 + 12_bij3 + 3_bij3.
		

Crossrefs

Programs

  • Maple
    b:= proc(n, k) option remember; `if`(n=0, [1, 0], add((p->
          [p[1], p[2]*k+p[1]*d])(b(n-d, k)), d=1..min(n, k)))
        end:
    a:= n-> b(n$2)[2]:
    seq(a(n), n=0..23);
  • Mathematica
    b[n_, k_] := b[n, k] = If[n == 0, {1, 0}, Sum[Function[p,{p[[1]], p[[2]]*k + p[[1]]*d}][b[n - d, k]], {d, 1, Min[n, k]}]];
    a[n_] := b[n, n][[2]];
    a /@ Range[0, 23] (* Jean-François Alcover, Apr 23 2021, after Alois P. Heinz *)

Formula

a(n) = ((n+1)^n - 2^n) / (n - 1) for n >= 2. - Peter Bala, Sep 28 2023
Previous Showing 11-13 of 13 results.