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.

A090103 n written in base equal to the number of distinct prime factors of n and a(1)=0.

Original entry on oeis.org

0, 11, 111, 1111, 11111, 110, 1111111, 11111111, 111111111, 1010, 11111111111, 1100, 1111111111111, 1110, 1111, 1111111111111111, 11111111111111111, 10010, 1111111111111111111, 10100, 10101, 10110, 11111111111111111111111, 11000
Offset: 1

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Author

Labos Elemer, Dec 16 2003

Keywords

Comments

All primes p are written in number-system of base one so rather long strings of 11...111 arise.

Examples

			a(6469693230) = 6469693230.
Symbol A to denote "10" first appears at n = 200560490130 = A002110(11).
		

Crossrefs

Cf. A002110, A001221, A031974 (primes in base one).

Programs

  • Mathematica
    tn[x_] := Fold[nd, 0, x]; Do[s=lf[n];If[Equal[s, 1], Print[tn[Table[1, {i, 1, n}]]]]; If[ !Equal[s, 1], Print[tn[IntegerDigits[n, s]]]], {n, 2, 211}]

Formula

n in base A001221(n).