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.

A000655 a(n) = number of letters in a(n-1), a(1) = 1 (in English).

Original entry on oeis.org

1, 3, 5, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4
Offset: 1

Views

Author

N. J. A. Sloane

Keywords

Comments

Decimal expansion of 1219/900. - Elmo R. Oliveira, May 05 2024

Examples

			One, three, five, four, four, four, ...

Links

Crossrefs

Cf. A005589 (number of letters).
Cf. A061504 (French), A101432 (Spanish), A328263 (Polish).

Programs

  • Mathematica
    Nest[Append[#, StringLength@ IntegerName[#[[-1]], "Words"]] &, {1}, 105] (* Michael De Vlieger, Feb 17 2021 *)

Formula

a(n) = 4 for n > 3, with a(1) = 1, a(2) = 3 and a(3) = 5. - Wesley Ivan Hurt, Oct 03 2020
E.g.f.: - 4 - 3*x - (1/2)*x^2 + (1/6)*x^3 + 4*exp(x). - Alejandro J. Becerra Jr., Feb 17 2021
G.f.: x*(1+2*x+2*x^2-x^3)/(1-x). - Elmo R. Oliveira, Jun 25 2024

A101432 Each term is the number of letters in the Spanish name of the previous term.

Original entry on oeis.org

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

Views

Author

Kevin Langdon (kevin.langdon(AT)polymath-systems.com), Jan 17 2005; corrected May 24 2005

Keywords

Examples

			Uno tres cuatro seis cuatro seis ...

Links

Crossrefs

Cf. A011762 (number of letters).
Cf. A000655 (English), A061504 (French), A328263 (Polish).

Formula

a(n) = 5-(-1)^n for n>1, with a(0)=1 and a(1)=3. - Wesley Ivan Hurt, Oct 03 2020

Extensions

More terms from Kara A. Houck (kah979(AT)psu.edu), Apr 20 2006

A061504 a(1) = 1; for n>1, a(n) = numbers of letters in French name for a(n-1).

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Jun 14 2001

Keywords

Comments

a(n+1) = le nombre des lettres dans a(n), a(1) = 1 (in French).
The English (1, 3, 5, 4, 4, 4, ...) and German (1, 4, 4, 4, ...) versions are less interesting.
Decimal expansion of 13847/11110 = 1.24635463546354635... - Eric Angelini, Sep 17 2006; corrected by Elmo R. Oliveira, Jun 29 2024

Examples

			Un, deux, quatre, six, trois, cinq, quatre, ...
UN (2 letters), DEUX (4 letters), QUATRE (6 letters), SIX (3 letters), TROIS (5 letters), CINQ (4 letters), QUATRE (6 letters), ...

Links

Crossrefs

Cf. A007005 (number of letters).
Cf. A000655 (English), A101432 (Spanish), A328263 (Polish).

Formula

From Elmo R. Oliveira, Jun 29 2024: (Start)
G.f.: x*(1+2*x+4*x^2+6*x^3+2*x^4+3*x^5)/(1-x^4).
a(n) = a(n-4) for n > 6. (End)

Extensions

Edited by N. J. A. Sloane at the suggestion of Andrew S. Plewe, Jun 08 2007
Showing 1-3 of 3 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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