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 1-2 of 2 results.

A189103 Least common multiple of n! and its arithmetic derivative.

Original entry on oeis.org

0, 2, 30, 264, 7320, 30960, 1592640, 38183040, 394450560, 2238969600, 275106585600, 4038941491200, 689773321036800, 20996629900646400, 111964387062528000, 2210304446558208000, 642338416210563072000, 19249748121316737024000, 6980209591900198477824000
Offset: 1

Views

Author

Giorgio Balzarotti, Apr 16 2011

Keywords

Examples

			n = 5: 5! = 120, 120' = 244, lcm(120,244) = 7320 -> a(5) = 7320
		

Crossrefs

Formula

a(n) = lcm(n!,n!') = lcm(A000142(n),A068311(n)).

A188901 Integers in the sequences (arithmetic derivative of k) divided by k.

Original entry on oeis.org

0, 1, 2, 1, 3, 2, 4, 3, 2, 5, 4, 3, 1, 6, 5, 4, 2, 7, 3, 6, 5, 3, 8, 4, 2, 7, 6, 4, 9, 5, 3, 8, 4, 7, 5, 1, 10, 6, 4, 9, 5, 3, 8, 6, 2, 11, 7, 5, 10, 6, 4, 2, 9, 7, 3, 5, 12, 8, 6, 2, 11, 7, 5, 3, 10, 8, 4, 6, 4, 13, 9, 7, 3, 12, 8, 6, 4, 11
Offset: 1

Views

Author

Giorgio Balzarotti, Apr 16 2011

Keywords

Comments

Integers in the sequence (k'/k) = A003415(k)/k. See A072873 for the values of k where k'/k is an integer.

Examples

			1' = 0, 0/1 = 0 -> a(1) = 0;
4' = 4 ,4/4 = 1 -> a(2) = 1;
16' = 32, 32/16 = 2 -> a(3) = 2.
		

Crossrefs

Showing 1-2 of 2 results.