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A062677 Numbers with property that every divisor (except 1) contains the digit 8. 2
83, 89, 181, 281, 283, 383, 389, 487, 587, 683, 787, 809, 811, 821, 823, 827, 829, 839, 853, 857, 859, 863, 877, 881, 883, 887, 983, 1087, 1181, 1187, 1283, 1289, 1381, 1481, 1483, 1487, 1489, 1583, 1783, 1787, 1789, 1801, 1811, 1823, 1831, 1847, 1861 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Subsequence of A011538, numbers with an 8. - Michel Marcus, Nov 21 2015

LINKS

Table of n, a(n) for n=1..47.

EXAMPLE

7387 has divisors 83, 89 and 7387, all of which contain the digit 8

MAPLE

isA062677 := proc(n)

    if n = 1 then

        return false;

    end if;

    for d in numtheory[divisors](n) minus {1} do

        convert(convert(d, base, 10), set) ;

        if  not 8 in % then

            return false;

        end if;

    end do:

    true ;

end proc:

for n from 1 to 2000 do

    if isA062677(n) then

        printf("%d, ", n) ;

    end if;

end do: # R. J. Mathar, Mar 27 2017

MATHEMATICA

fQ[n_, dgt_] := Union[ MemberQ[#, dgt] & /@ IntegerDigits@ Rest@ Divisors@ n][[1]]; Select[ Range[2, 1900], fQ[#, 8] &] (* Robert G. Wilson v, Jun 11 2014 *)

Select[Prime[Range[350]], !StringFreeQ[ToString[#], "8"] &] (* Vincenzo Librandi, Nov 21 2015 *)

PROG

(MAGMA) [p: p in PrimesUpTo(2000) |  8 in Intseq(p)]; // Vincenzo Librandi, Nov 21 2015

CROSSREFS

Sequence in context: A307733 A130286 A226380 * A284292 A045714 A090156

Adjacent sequences:  A062674 A062675 A062676 * A062678 A062679 A062680

KEYWORD

base,easy,nonn

AUTHOR

Erich Friedman, Jul 04 2001

STATUS

approved

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Last modified October 22 19:53 EDT 2019. Contains 328319 sequences. (Running on oeis4.)