A244356 Numbers n such that n and n+1 are not divisible by any of their nonzero digits.

37, 46, 53, 56, 57, 58, 67, 68, 73, 78, 86, 97, 307, 337, 346, 358, 373, 376, 379, 388, 397, 406, 429, 433, 446, 457, 466, 469, 473, 477, 478, 489, 493, 498, 506, 507, 508, 538, 553, 556, 557, 558, 577, 578, 586, 587, 588, 596, 597, 598, 646, 656, 657, 658, 667, 668, 669

Offset

1,1

Comments

This is a subsequence of A038772.

All numbers end in a 3, 6, 7, 8, or 9.

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

37 is not divisible by 3 or 7 and 38 is not divisible by 3 or 8. Thus 37 is a member of this sequence.

Maple

filter:= proc(n) local L;
  L:= convert(convert(n, base, 10), set) minus {0};
  not ormap(t -> n mod t = 0, L)
end proc:
B:= select(filter, {$1..1000}):
sort(convert(B intersect map(`-`, B, 1), list)); # Robert Israel, Dec 08 2019

Prog

(Python)
def a(n):
  for i in range(10**3):
    tot = 0
    for k in range(i, i+n):
      c = 0
      for b in str(k):
        if b != '0':
          if k%int(b)!=0:
            c += 1
      if c == len(str(k))-str(k).count('0'):
        tot += 1
    if tot == n:
      print(i, end=', ')
a(2)

Crossrefs

Cf. A038772, A237766.

Sequence in context: A043174 A043954 A349057 * A159750 A108333 A231254

Adjacent sequences: A244353 A244354 A244355 * A244357 A244358 A244359

Keyword

nonn,base,look

Author

Derek Orr, Jun 26 2014

Status

approved