login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A039935 Smallest k for which k, 2k, ... nk all contain the digit 4. 9
4, 24, 47, 471, 487, 1248, 1249, 6248, 6249, 6249, 12493, 12493, 12493, 12493, 12498, 31249, 62499, 62499, 62499, 62499, 62499, 62499, 62499, 62499, 62499, 62499, 62499, 62499, 62499, 62499, 62499, 312497, 312497, 312497, 624984, 624984, 624984, 624984, 624984 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Giovanni Resta, Table of n, a(n) for n = 1..2047

EXAMPLE

a(3) = 47 since 47, 94 and 141 all contain a 4.

PROG

(Python)

def aupton(terms):

  k, n, alst = 1, 1, []

  while len(alst) < terms:

    while not all(str(i*k).count('4') > 0 for i in range(1, n+1)): k += 1

    while str(n*k).count('4') > 0: alst.append(k); n += 1

    k += 1

  return alst[:terms]

print(aupton(39)) # Michael S. Branicky, Apr 24 2021

CROSSREFS

Cf. A039932, A039933, A039934, A039936, A039937, A039938, A039939, A039940.

Sequence in context: A224242 A066770 A080380 * A090821 A226575 A052645

Adjacent sequences:  A039932 A039933 A039934 * A039936 A039937 A039938

KEYWORD

base,nonn

AUTHOR

Erich Friedman

EXTENSIONS

More terms from Patrick De Geest, Oct 15 1999

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 25 11:50 EDT 2022. Contains 354071 sequences. (Running on oeis4.)