A062649 - OEIS

A062649

Composite numbers with property that every divisor contains the digit 1.

121, 143, 169, 187, 221, 341, 361, 451, 671, 781, 961, 1037, 1111, 1133, 1159, 1177, 1199, 1207, 1243, 1271, 1313, 1331, 1339, 1349, 1391, 1397, 1417, 1441, 1469, 1507, 1529, 1573, 1639, 1651, 1661, 1681, 1703, 1717, 1727, 1751, 1781, 1793, 1807, 1819

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Intersection of A002808 and A062634. - Michel Marcus, Sep 12 2013

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

EXAMPLE

143 has divisors 1, 11, 13 and 143, all of which contain the digit 1.

MATHEMATICA

fQ[n_, dgt_] := Union[ MemberQ[#, dgt] & /@ IntegerDigits@ Rest@ Divisors@ n][[1]]; Select[ Range[2, 1850], !PrimeQ[#] && fQ[#, 1] &] (* Robert G. Wilson v, Jun 11 2014 *)

PROG

(PARI) lista(nn) = {forcomposite(n = 1, nn, ok = 1; fordiv(n, d, ok = ok && setsearch(Set(digits(d)), 1)); if (ok, print1(n, ", ")); ); } \\ Michel Marcus, Sep 12 2013

CROSSREFS

Cf. A062634, A062653, A062664, A062667, A062669, A062670, A062671, A062672, A062673, A062674, A062675, A062676, A062677, A062678, A062679, A062680.

Sequence in context: A271630 A038511 A285784 * A206288 A287390 A258202

Adjacent sequences: A062646 A062647 A062648 * A062650 A062651 A062652

KEYWORD

base,easy,nonn

AUTHOR

Erich Friedman, Jul 04 2001

STATUS

approved