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A196879 Square array A(n,k), n>=0, k>=0, read by antidiagonals: A(n,k) is the number of partitions of n^k into powers of k. 20
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 4, 1, 1, 1, 1, 3, 10, 1, 1, 1, 1, 6, 23, 36, 1, 1, 1, 1, 9, 72, 132, 94, 1, 1, 1, 1, 16, 335, 1086, 729, 284, 1, 1, 1, 1, 36, 2220, 15265, 15076, 3987, 692, 1, 1, 1, 1, 85, 19166, 374160, 642457, 182832, 18687, 1828, 1, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,13

LINKS

Alois P. Heinz, Antidiagonals n = 0..44, flattened

FORMULA

For k>1: A(n,k) = [x^(n^k)] 1/Product_{j>=0}(1-x^(k^j)).

EXAMPLE

A(2,3) = 3, because the number of partitions of 2^3=8 into powers of 3 is 3: [1,1,3,3], [1,1,1,1,1,3], [1,1,1,1,1,1,1,1].

Square array A(n,k) begins:

  1,  1,  1,   1,     1,      1,  ...

  1,  1,  1,   1,     1,      1,  ...

  1,  1,  4,   3,     6,      9,  ...

  1,  1, 10,  23,    72,    335,  ...

  1,  1, 36, 132,  1086,  15265,  ...

  1,  1, 94, 729, 15076, 642457,  ...

MAPLE

b:= proc(n, j, k) local nn, r;

      if n<0 then 0

    elif j=0 then 1

    elif j=1 then n+1

    elif n<j then b(n, j, k):= b(n-1, j, k) +b(k*n, j-1, k)

             else nn:= 1 +floor(n);

                  r:= n-nn;

                  (nn-j) *binomial(nn, j) *add(binomial(j, h)

                  /(nn-j+h) *b(j-h+r, j, k) *(-1)^h, h=0..j-1)

      fi

    end:

A:= proc(n, k) local s, t;

      if k<2 then return 1 fi;

      s:= floor(n^k/k);

      t:= ilog[k](k*s+1);

      b(s/k^(t-1), t, k)

    end:

seq(seq(A(n, d-n), n=0..d), d=0..15);

MATHEMATICA

a[_, 0] = a[_, 1] = a[0, _] = a[1, _] = 1; a[n_, k_] := SeriesCoefficient[ 1/Product[ (1 - x^(k^j)), {j, 0, n}], {x, 0, n^k}]; Table[a[n - k, k], {n, 0, 10}, {k, n, 0, -1}] // Flatten (* Jean-Fran├žois Alcover, Dec 09 2013 *)

CROSSREFS

Columns k=0+1, 2-10 give: A000012, A196880, A196881, A196882, A196883, A196884, A196885, A196886, A196887, A196888.

Rows n=0+1, 2-10 give: A000012, A196889, A196890, A196891, A196892, A196893, A196894, A196895, A196896, A196897.

Main diagonal gives: A145514.

Cf. A145515.

Sequence in context: A046564 A046592 A010326 * A193349 A053231 A066701

Adjacent sequences:  A196876 A196877 A196878 * A196880 A196881 A196882

KEYWORD

nonn,tabl

AUTHOR

Alois P. Heinz, Oct 07 2011

STATUS

approved

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Last modified January 25 07:24 EST 2020. Contains 331241 sequences. (Running on oeis4.)