A062675 Every divisor (except 1) contains the digit 7.

7, 17, 37, 47, 67, 71, 73, 79, 97, 107, 127, 137, 157, 167, 173, 179, 197, 227, 257, 271, 277, 307, 317, 337, 347, 367, 373, 379, 397, 457, 467, 479, 487, 497, 547, 557, 571, 577, 587, 607, 617, 647, 673, 677, 679, 701, 709, 719, 727, 733, 739, 743, 749, 751

Offset

1,1

Links

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

Example

799 has divisors 17, 47 and 799, all of which contain the digit 7.

Mathematica

fQ[n_, dgt_] := Union[ MemberQ[#, dgt] & /@ IntegerDigits@ Rest@ Divisors@ n][[1]]; Select[ Range[2, 760], fQ[#, 7] &]  (* Robert G. Wilson v, Jun 11 2014 *)

Prog

(Magma) [k:k in [2..800]| forall{d:d in Set(Divisors(k)) diff {1}| 7 in Intseq(d)}]; // Marius A. Burtea, Nov 07 2019

Crossrefs

Cf. A062653, A062664, A062667, A062668, A062669, A062670, A062671, A062672, A062673, A062674, A062676, A062677, A062678, A062679, A062680.

Sequence in context: A160635 A339527 A090652 * A257668 A106095 A153319

Adjacent sequences: A062672 A062673 A062674 * A062676 A062677 A062678

Keyword

nonn,base,easy

Author

Erich Friedman, Jul 04 2001

Status

approved