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 1-7 of 7 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

Views

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).

A091581 Number of partitions of n into distinct decimal palindromes.

Original entry on oeis.org

1, 1, 1, 2, 2, 3, 4, 5, 6, 8, 9, 11, 13, 14, 17, 19, 21, 23, 26, 27, 30, 32, 34, 36, 37, 39, 40, 42, 42, 44, 44, 45, 45, 47, 47, 47, 49, 48, 50, 50, 52, 52, 55, 55, 58, 60, 60, 64, 65, 68, 69, 73, 73, 77, 78, 82, 84, 84, 88, 88, 92, 92, 96, 96, 100, 100, 105, 107, 107, 113
Offset: 0

Views

Author

Reinhard Zumkeller, Jan 22 2004

Keywords

Comments

Not the same as A088670: a(n) > A088670(n) for n > 101.

Examples

			n=13: there are A000009(13)=18 partitions of 13 into distinct integers, 4 of them contain non-palindromes: 13=12+1, 13=10+3, 13=10+2+1 and 13 itself, therefore a(13)=18-4=14;
for n=14 there are a(14)=17 partitions into palindromes: 11+3 = 11+2+1 = 9+5 = 9+4+1 = 9+3+2 = 8+6 = 8+5+1 = 8+4+2 = 8+3+2+1 = 7+6+1 = 7+5+2 = 7+4+3 = 7+4+2+1 = 6+5+3 = 6+5+2+1 = 6+4+3+1 = 5+4+3+2.
		

Crossrefs

Extensions

a(0)=1 prepended by Alois P. Heinz, Sep 17 2018

A088669 Number of partitions of n into decimal repdigit numbers.

Original entry on oeis.org

1, 1, 2, 3, 5, 7, 11, 15, 22, 30, 41, 55, 74, 96, 126, 162, 208, 263, 333, 415, 518, 639, 788, 962, 1174, 1420, 1716, 2060, 2468, 2940, 3497, 4137, 4886, 5747, 6744, 7885, 9203, 10702, 12424, 14379, 16611, 19136, 22009, 25245, 28915, 33037, 37688, 42901, 48765
Offset: 0

Views

Author

Reinhard Zumkeller, Oct 03 2003

Keywords

Comments

Different from A091580: a(101) is one less than A091580(101) and thereafter the difference steadily increases. - Joshua Zucker, May 10 2007
a(n) <= A000041(n).

Crossrefs

Cf. A010785, A088670. Different from A091580.
Cf. A131361.

Extensions

a(0)=1 prepended by Alois P. Heinz, Jan 18 2016

A282584 Number of compositions (ordered partitions) of n into decimal palindromes (A002113).

Original entry on oeis.org

1, 1, 2, 4, 8, 16, 32, 64, 128, 256, 511, 1022, 2042, 4081, 8156, 16300, 32576, 65104, 130112, 260032, 519681, 1038595, 2075660, 4148259, 8290402, 16568581, 33112734, 66176648, 132255728, 264316464, 528243231, 1055707644, 2109858797, 4216606912, 8426997041, 16841569684, 33658308890, 67266993433
Offset: 0

Views

Author

Ilya Gutkovskiy, Feb 19 2017

Keywords

Examples

			a(4) = 8 because we have [4], [3, 1], [2, 2], [2, 1, 1], [1, 3], [1, 2, 1], [1, 1, 2] and [1, 1, 1, 1].
		

Crossrefs

Programs

  • Mathematica
    nmax = 37; CoefficientList[Series[1/(1 - Sum[Boole[PalindromeQ[k]] x^k, {k, 1, nmax}]), {x, 0, nmax}], x]

Formula

G.f.: 1/(1 - Sum_{k>=2} x^A002113(k)).

A282585 Number of ways to write n as an ordered sum of 3 squarefree palindromes (A071251).

Original entry on oeis.org

0, 0, 0, 1, 3, 6, 7, 9, 12, 19, 21, 21, 18, 24, 27, 28, 18, 18, 19, 24, 15, 10, 6, 12, 12, 12, 9, 9, 12, 15, 18, 12, 9, 7, 15, 15, 15, 9, 12, 15, 18, 18, 12, 9, 9, 18, 15, 12, 0, 9, 9, 9, 0, 0, 0, 6, 6, 9, 12, 9, 12, 15, 18, 18, 12, 9, 13, 18, 18, 18, 9, 15, 18, 21, 18, 12, 9, 15, 21, 21, 21, 9, 18, 21, 24, 18
Offset: 0

Views

Author

Ilya Gutkovskiy, Feb 19 2017

Keywords

Comments

Every number can be written as the sum of 3 palindromes (see A261132 and A261422).
Conjecture: a(n) > 0 for any sufficiently large n.
Additional conjecture: every number > 3 can be written as the sum of 4 squarefree palindromes.

Examples

			a(22) = 6 because we have [11, 6, 5], [11, 5, 6] [6, 11, 5], [6, 5, 11], [5, 11, 6] and [5, 6, 11].
		

Crossrefs

Programs

  • Mathematica
    nmax = 85; CoefficientList[Series[Sum[Boole[SquareFreeQ[k] && PalindromeQ[k]] x^k, {k, 1, nmax}]^3, {x, 0, nmax}], x]

Formula

G.f.: (Sum_{k>=1} x^A071251(k))^3.

A091584 Number of partitions of the n-th decimal palindrome into decimal palindromes.

Original entry on oeis.org

1, 1, 2, 3, 5, 7, 11, 15, 22, 30, 55, 788, 5747, 28915, 114064, 378823, 1105429, 2916219, 7093435, 8275126, 17341313, 34721974, 66837990, 124308827, 224290376, 393929311, 675393430, 1133103539, 1864009161, 3157186031, 5011108578, 7836124010, 12086660443
Offset: 1

Views

Author

Reinhard Zumkeller, Jan 22 2004

Keywords

Comments

a(n) = A091580(A002113(n)).

Crossrefs

Extensions

More terms from Alois P. Heinz, Nov 13 2018

A338847 Number of compositions (ordered partitions) of n into distinct decimal palindromes.

Original entry on oeis.org

1, 1, 1, 3, 3, 5, 11, 13, 19, 27, 56, 63, 98, 122, 180, 324, 376, 538, 710, 962, 1130, 2202, 2341, 3410, 4226, 5276, 6692, 8324, 13940, 15476, 21692, 22394, 32952, 33555, 43418, 47738, 93002, 92282, 101666, 136346, 140810, 176186, 176336, 212448
Offset: 0

Views

Author

Ilya Gutkovskiy, Nov 11 2020

Keywords

Crossrefs

Showing 1-7 of 7 results.