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.

A256870 Numbers divisible by prime(d+1) for each digit d of their base-10 representation.

Original entry on oeis.org

0, 20, 44, 111, 120, 171, 200, 210, 220, 290, 440, 520, 1020, 1110, 1113, 1200, 1710, 1914, 2000, 2010, 2020, 2030, 2100, 2145, 2200, 2220, 2310, 2420, 2900, 3220, 3381, 4004, 4048, 4400, 4444, 5200, 5525, 6120, 7220, 8280, 9338
Offset: 1

Views

Author

M. F. Hasler, Apr 11 2015

Keywords

Comments

A variant of A256786 where digits 0 are forbidden and divisibility by prime(d) is required.
See A256882 - A256884, A256866 - A256869 for the analog in bases 2, ..., 9.

Examples

			0 is divisible by prime(0+1)=2.
n = 1,...,9 are not divisible by prime(n+1) = 3, 5, ..., 29, respectively.
20 is divisible by prime(2+1)=5 and by prime(0+1)=2. The same is true for any other 2...20...0 =  2*10^k*(10^m-1)/9; k >= 1, m >= 0.
44 is divisible by prime(4+1)=11.
		

Crossrefs

Programs

  • PARI
    is(n,b=10)=!for(i=1,#d=Set(digits(n,b)),n%prime(d[i]+1)&&return)