A229123 a(n) gives the number of bases, b>1, in which n is an early bird.

0, 0, 1, 0, 2, 2, 3, 2, 3, 2, 4, 3, 6, 4, 5, 3, 7, 2, 7, 5, 7, 6, 7, 4, 9, 7, 6, 5, 8, 5, 10, 4, 8, 8, 7, 5, 13, 8, 8, 6, 12, 7, 12, 7, 8, 11, 11, 5, 13, 9, 12, 9, 11, 5, 13, 11, 13, 12, 12, 5, 17, 11, 11, 8, 13, 9, 14, 9, 12, 7, 14, 8, 18, 11, 9, 11, 13, 11

Offset

1,5

Comments

A number n is called an early bird in base b, if its digits in base b appear in the concatenation of the digits in base b of the numbers from 1 to n-1.

Links

Paul Tek, Table of n, a(n) for n = 1..10000

Paul Tek, C program for this sequence

Paul Tek, Illustration of the bases in which n is an early bird, where n ranges from 1 to 1000

Example

The number 1 is never an early bird, so a(1)=0.
The number 3 is an early bird only in base 2, so a(3)=1.
The number 7 is an early bird in bases 2, 3 and 5, so a(7)=3.

Prog

(C) See Link section.

Crossrefs

Cf. A116700, A161373, A135549.

Sequence in context: A327161 A350067 A308450 * A173908 A329045 A329345

Adjacent sequences: A229120 A229121 A229122 * A229124 A229125 A229126

Keyword

nonn,base

Author

Paul Tek, Sep 14 2013

Status

approved