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.

A102420 Number of partitions of n into exactly k = 5 parts with each part p <= 5.

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 1, 2, 3, 5, 6, 8, 9, 11, 11, 12, 11, 11, 9, 8, 6, 5, 3, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
Offset: 0

Views

Author

Thomas Wieder, Jan 09 2005

Keywords

Comments

There are only 26 nonzero terms.
a(n) is also the number of partitions of n-1 into exactly 4 parts with each part p in the range 1 <= p <= 6; i.e. the number of ways of arriving at a total of n-1 with 4 6-sided dice. - Toby Gottfried, Feb 19 2009

Examples

			a(8) = 3 because we can write 8=1+1+1+2+3 or 1+1+1+1+4 or 1+1+2+2+2.
		

Crossrefs

Programs

Formula

G.f.:z^5+z^6+2*z^7+3*z^8+5*z^9+6*z^10+8*z^11+9*z^12+11*z^13 +11*z^14 +12*z^15+ 11*z^16+11*z^17+9*z^18+8*z^19+6*z^20+5*z^21+3*z^22 +2*z^23 +z^24 +z^25.

A107110 Square array by antidiagonals where T(n,k) is the number of partitions of k into no more than n parts each no more than n. Visible version of A063746.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 0, 2, 1, 1, 0, 0, 1, 2, 1, 1, 0, 0, 1, 3, 2, 1, 1, 0, 0, 0, 3, 3, 2, 1, 1, 0, 0, 0, 3, 5, 3, 2, 1, 1, 0, 0, 0, 3, 5, 5, 3, 2, 1, 1, 0, 0, 0, 2, 7, 7, 5, 3, 2, 1, 1, 0, 0, 0, 1, 7, 9, 7, 5, 3, 2, 1, 1, 0, 0, 0, 1, 8, 11, 11, 7, 5, 3, 2, 1, 1, 0, 0, 0, 0, 7, 14, 13, 11, 7, 5, 3, 2
Offset: 0

Views

Author

Henry Bottomley, May 12 2005

Keywords

Examples

			Rows start 1,0,0,0,...; 1,1,0,0,0,...; 1,1,2,1,1,0,0,0,...; 1,1,2,3,3,3,3,2,1,1,0,0,0,...; 1,1,2,3,5,5,7,7,8,7,7,5,5,3,2,1,1,0,0,0,...; etc.
T(4,6)=7 since 6 can be written seven ways with no more than 4 parts each no more than 4: 4+2, 4+1+1, 3+3, 3+2+1, 3+1+1+1, 2+2+2, or 2+2+1+1.
		

Crossrefs

Cf. A063746. Fifth row is A102422.

Formula

See A063746 for formulas. T(n, k)=A000041(k) if n>=k. T(n, k)=T(n, n^2-k). T(n, [n^2/2])=A029895(n); T(2n, 2n^2)=A063074(n). Row sums are A000984.

A127500 On the triangular peg solitaire board of side n, the shortest solution to any problem beginning with one peg missing and ending with one peg.

Original entry on oeis.org

5, 9, 9, 12, 13, 16, 18
Offset: 4

Views

Author

George Bell (gibell(AT)comcast.net), Mar 31 2007

Keywords

Comments

Shortest means the minimum number of moves, where a move is one or more jumps by the same peg. The reference calculates a(n) up to n=10 and gives the bounds 19<=a(11)<=28, 21<=a(12)<=29, as well as an upper bound for n a multiple of 12. A trivial upper bound is a(n)<=T(n)-2, where T(n) is the n-th triangular number.

Examples

			a(4)=5, the 10-hole triangular board can be solved in 5 moves (and always 8 jumps).
		

References

  • Martin Gardner, Penny Puzzles, in Mathematical Carnival, p. 12-26, Alfred A. Knopf, Inc., 1975

Crossrefs

Showing 1-3 of 3 results.