A132080 Numbers having in decimal representation no common digits with all their proper divisors.

2, 3, 4, 5, 6, 7, 8, 9, 23, 27, 29, 34, 37, 38, 43, 46, 47, 49, 53, 54, 56, 57, 58, 59, 67, 68, 69, 73, 76, 78, 79, 83, 86, 87, 89, 97, 223, 227, 229, 233, 239, 247, 249, 257, 259, 263, 267, 269, 277, 283, 289, 293, 307, 323, 329, 334, 337, 347, 349, 353, 356, 358, 359

Offset

1,1

Comments

A038603 is a subsequence.

Links

R. Zumkeller, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Proper Divisor

Example

Proper divisors of a(20)=54: {1, 2, 3, 6, 9, 18, 27}
with set of digits {1,2,3,6,7,8,9} containing neither 4 nor 5.

Prog

(Haskell)
import Data.List (intersect)
a132080 n = a132080_list !! (n-1)
a132080_list = [x | x <- [2..], all null $
                    map (show x `intersect`) $ map show $ a027751_row x]
-- Reinhard Zumkeller, Oct 06 2012
(PARI) is(n)=my(D=Set(digits(n))); fordiv(n, d, if(#setintersect(D, Set(digits(d))), return(d==n&&n>1))) \\ Charles R Greathouse IV, Dec 01 2013

Crossrefs

Subsequence of A052383.

Sequence in context: A061672 A272814 A322516 * A307636 A373722 A048386

Adjacent sequences: A132077 A132078 A132079 * A132081 A132082 A132083

Keyword

nonn,base

Author

Reinhard Zumkeller, Aug 09 2007

Status

approved