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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A133375 Catalan numbers with digits sorted in increasing order and zeros suppressed.

Original entry on oeis.org

1, 1, 2, 5, 14, 24, 123, 249, 134, 2468, 16679, 56788, 1228, 2479, 244467, 4456899, 3355677, 12446799, 3467778, 112366779, 12244566, 222446667, 1234456689, 1333455669, 112234447899
Offset: 0

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Author

Jonathan Vos Post, Dec 21 2007

Keywords

Comments

This is to A000108 as A135374 is to A000225 and as A078726 is to A000215. Of the values through a(24), the only primes are the two prime Catalan numbers 2 and 5. What is the first prime in this sequence which is not an untransformed Catalan number?

Crossrefs

Cf. A000108, A004185, A078726, A135374.

Programs

  • Mathematica
    FromDigits[Sort[IntegerDigits[#]]]&/@CatalanNumber[Range[0,30]] (* Harvey P. Dale, Feb 26 2015 *)

Formula

A004185(A000108(n)) = A004185((2n)!/(n!(n+1)!)).
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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