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.

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A113589 A complementary variation of 'n described': if n is read as "a ones b twos" then a(n) = "one a's two b's", etc.

Original entry on oeis.org

0, 1, 11, 111, 1111, 11111, 111111, 1111111, 11111111, 111111111, 1, 2, 111, 1111, 11111, 111111, 1111111, 11111111, 111111111, 1111111111, 11, 111, 22, 11111, 111111, 1111111, 11111111, 111111111, 1111111111, 11111111111, 111, 1111, 11111, 222
Offset: 0

Views

Author

Amarnath Murthy, Nov 07 2005

Keywords

Examples

			A045918(10) = 1110 = 'one one one zero', hence a(10) = 'one one, zero ones' = 1.
A045918(11) = 21 = 'two ones', hence a(11) = 'one twos' = 2.
a(123) = 111111.
		

Crossrefs

Programs

  • PARI
    a(n) = { my (d=[]); while (n, my (t=n%10, k=0); while (n%10==t, n\=10; k++;); for (i=1, t, d=concat(digits(k), d))); fromdigits(d) } \\ Rémy Sigrist, Feb 09 2022

Formula

a(A002275(n)) = n. - Rémy Sigrist, Feb 09 2022

Extensions

Extended and corrected by Nathaniel Johnston, Apr 29 2011
a(0) = 0 prepended by Rémy Sigrist, Feb 09 2022
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