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.

A319453 Number T(n,k) of partitions of n into exactly k nonzero decimal palindromes; triangle T(n,k), n>=0, 0<=k<=n, read by rows.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 2, 1, 1, 0, 1, 2, 2, 1, 1, 0, 1, 3, 3, 2, 1, 1, 0, 1, 3, 4, 3, 2, 1, 1, 0, 1, 4, 5, 5, 3, 2, 1, 1, 0, 1, 4, 7, 6, 5, 3, 2, 1, 1, 0, 0, 5, 8, 9, 7, 5, 3, 2, 1, 1, 0, 1, 4, 10, 11, 10, 7, 5, 3, 2, 1, 1, 0, 0, 5, 11, 15, 13, 11, 7, 5, 3, 2, 1, 1
Offset: 0

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Author

Alois P. Heinz, Sep 19 2018

Keywords

Comments

Differs from A008284 and from A072233 first at T(10,1) = 0.

Examples

			Triangle T(n,k) begins:
  1;
  0, 1;
  0, 1, 1;
  0, 1, 1,  1;
  0, 1, 2,  1,  1;
  0, 1, 2,  2,  1,  1;
  0, 1, 3,  3,  2,  1,  1;
  0, 1, 3,  4,  3,  2,  1, 1;
  0, 1, 4,  5,  5,  3,  2, 1, 1;
  0, 1, 4,  7,  6,  5,  3, 2, 1, 1;
  0, 0, 5,  8,  9,  7,  5, 3, 2, 1, 1;
  0, 1, 4, 10, 11, 10,  7, 5, 3, 2, 1, 1;
  0, 0, 5, 11, 15, 13, 11, 7, 5, 3, 2, 1, 1;
  ...
		

Crossrefs

Columns k=0-10 give: A000007, A136522 (for n>0), A319468, A261131, A319469, A319470, A319471, A319472, A319473, A319474, A319475.
Row sums give A091580.
T(2n,n) gives A319454.

Programs

  • Maple
    p:= proc(n) option remember; local i, s; s:= ""||n;
          for i to iquo(length(s), 2) do if
            s[i]<>s[-i] then return false fi od; true
        end:
    h:= proc(n) option remember; `if`(n<1, 0,
         `if`(p(n), n, h(n-1)))
        end:
    b:= proc(n, i) option remember; `if`(n=0 or i=1, x^n,
          b(n, h(i-1))+expand(x*b(n-i, h(min(n-i, i)))))
        end:
    T:= n-> (p-> seq(coeff(p, x, i), i=0..n))(b(n, h(n))):
    seq(T(n), n=0..14);

Formula

T(n,k) = [x^n y^k] 1/Product_{j>=2} (1-y*x^A002113(j)).
Sum_{k=0..3} T(n,k) = A261132(n).

A341206 Number of ways to write n as an ordered sum of 9 nonzero decimal palindromes.

Original entry on oeis.org

1, 9, 45, 165, 495, 1287, 3003, 6435, 12870, 24301, 43686, 75249, 124809, 200115, 311157, 470415, 693000, 996633, 1401436, 1929465, 2603979, 3448440, 4485267, 5734395, 7211718, 8927523, 10885050, 13079257, 15496065, 18112050, 20894757, 23803659, 26791749, 29807697, 32798448
Offset: 9

Views

Author

Ilya Gutkovskiy, Feb 06 2021

Keywords

Crossrefs

Programs

  • Maple
    p:= proc(n) option remember; local i, s; s:= ""||n;
          for i to iquo(length(s), 2) do if
            s[i]<>s[-i] then return false fi od; true
        end:
    b:= proc(n, t) option remember; `if`(n=0, `if`(t=0, 1, 0),
          `if`(t<1, 0, add(`if`(p(j), b(n-j, t-1), 0), j=1..n)))
        end:
    a:= n-> b(n, 9):
    seq(a(n), n=9..43);  # Alois P. Heinz, Feb 07 2021
  • Mathematica
    nmax = 43; CoefficientList[Series[Sum[Boole[PalindromeQ[k]] x^k, {k, 1, nmax}]^9, {x, 0, nmax}], x] // Drop[#, 9] &

A341167 Number of partitions of n into 9 distinct nonzero decimal palindromes.

Original entry on oeis.org

1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 2, 2, 3, 3, 4, 4, 4, 4, 5, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 4, 4, 5, 5, 6, 6, 8, 8, 10, 11, 13, 12, 14, 14, 15, 15, 15, 15, 15, 15, 15, 16, 14, 15, 16, 16, 17, 17, 19, 19, 21, 22, 24, 22, 25, 25, 26, 26, 26, 27
Offset: 45

Views

Author

Ilya Gutkovskiy, Feb 06 2021

Keywords

Crossrefs

Showing 1-3 of 3 results.