OFFSET
1,1
COMMENTS
nDigits Count Min Max
------- ----- ---------- ----------
6 0
7 286 1633956 9985197
8 1254 11561774 99851332
9 1708 113245177 985113324
10 468 1123315817 9185132117
11 0
There are no 6-digit or 11-digit integers that produce the digits 0 to 9 by multiplication of two contiguous digits of N. The smallest such integer is 1633956; the largest one is 9185132117; the sequence has 3716 terms.
LINKS
Lars Blomberg, Table of n, a(n) for n = 1..3716
EXAMPLE
The first term is 1633956. The successive products of two contiguous digits of 1633956 are 1*6=6, 6*3=18, 3*3=9, 3*9=27, 9*5=45, 5*6=30. We see that 6, 18, 9, 27, 45 and 30 include all digits 0 to 9, none being repeated.
MATHEMATICA
Select[Range[163*10^4, 234*10^4], Sort[Flatten[IntegerDigits/@ (Times@@@ Partition[ IntegerDigits[ #], 2, 1])]]==Range[0, 9]&] (* Harvey P. Dale, Dec 17 2020 *)
CROSSREFS
KEYWORD
nonn,base,fini
AUTHOR
Eric Angelini and Lars Blomberg, Dec 13 2017
STATUS
approved