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.

A228586 Write the semiprimes backwards in base 10 and juxtapose (concatenate) their digits.

Original entry on oeis.org

4, 6, 9, 0, 1, 4, 1, 5, 1, 1, 2, 2, 2, 5, 2, 6, 2, 3, 3, 4, 3, 5, 3, 8, 3, 9, 3, 6, 4, 9, 4, 1, 5, 5, 5, 7, 5, 8, 5, 2, 6, 5, 6, 9, 6, 4, 7, 7, 7, 2, 8, 5, 8, 6, 8, 7, 8, 1, 9, 3, 9, 4, 9, 5, 9, 6, 0, 1, 1, 1, 1, 5, 1, 1, 8, 1, 1, 9, 1, 1, 1, 2, 1
Offset: 1

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Author

Jonathan Vos Post, Aug 26 2013

Keywords

Comments

Also, decimal expansion of the constant 0.46901415112225262... This is to A228355 as semiprimes A001358 are to prime A000040.
A theorem of Copeland & Erdős proves that this constant is 10-normal. - Charles R Greathouse IV, Feb 06 2015

Examples

			4, 6, 9, 01, 41, 51, 12, 22, 52, 62, 33, 43, 53, 83, 93, 64, 94, 15, 55,...
		

Crossrefs

Programs

  • PARI
    print1(4); for(n=6, 121, if(bigomega(n)==2, d=Vecrev(digits(n)); for(i=1, #d, print1(", "d[i])))) \\ Charles R Greathouse IV, Feb 06 2015