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.

A220660 Irregular table, where the n-th row consists of numbers 0..(n!-1).

Original entry on oeis.org

0, 0, 1, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39
Offset: 1

Views

Author

Antti Karttunen, Dec 18 2012

Keywords

Comments

Used for computing A030298: a(n) tells the zero-based ranking of the n-th permutation in A030298 (A030299(n)) in the lexicographical ordering of all finite permutations of the same size.

Examples

			Rows of this irregular table begin as:
0;
0, 1;
0, 1, 2, 3, 4, 5;
		

Crossrefs

Programs

Formula

a(n) = n - A007489(A084556(n)-1) - 1.
a(n) = A220661(n)-1.

A236857 Each n occurs the least common multiple (LCM) of {1, 2, ..., n} (= A003418(n)) times.

Original entry on oeis.org

0, 1, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6
Offset: 0

Views

Author

Antti Karttunen, Feb 27 2014

Keywords

Comments

Least k such that A236856(k) >= n.
Zero occurs once at a(0), because A003418(0)=1 by definition.
Useful when computing irregular tables like A238280, as a(n) gives the row index of the n-th term in such sequences. Note that as A238280 begins with row 1, it starts referring to this sequence only from a(1)=1 onward.

Examples

			Can be viewed as an irregular table, where each row n (starting from row zero) contains A003418(n) copies of n:
0;
1;
2, 2;
3, 3, 3, 3, 3, 3;
4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4;
...
		

Crossrefs

Programs

  • Mathematica
    Join[{0},Flatten[Table[PadRight[{},LCM@@Range[n],{n}],{n,6}]]] (* Harvey P. Dale, Jul 29 2021 *)

A220661 Irregular table, where the n-th row consists of numbers 1..n!

Original entry on oeis.org

1, 1, 2, 1, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39
Offset: 1

Views

Author

Antti Karttunen, Dec 18 2012

Keywords

Examples

			Rows of this irregular table begin as:
1;
1, 2;
1, 2, 3, 4, 5, 6;
		

Crossrefs

Programs

Formula

a(n) = n - A007489(A084556(n)-1).
a(n) = A220660(n)+1.
Previous Showing 11-13 of 13 results.