OFFSET
1,1
COMMENTS
These numbers are all repdigits belonging to A010785. The representation of the numbers 7 and 8 in base 10 is not Brazilian but they are yet Brazilian because 7 = 111_2 and 8 = 22_3. Except the repdigits 7, 8, 22, 33, 55, 77 and the primes repunits R_n from A004022 and A004023, all these Brazilian repdigits are also Brazilian in another base.
Contains all base-10 repdigits (A010785) >= 22, because these are Brazilian numbers in base 10. - R. J. Mathar, Jul 19 2024
LINKS
Index entries for linear recurrences with constant coefficients, signature (0, 0, 0, 0, 0, 0, 0, 0, 11, 0, 0, 0, 0, 0, 0, 0, 0, -10).
EXAMPLE
7 = 111_2;
44 = 44_10 = 22_21;
66 = 66_10 = 33_21 = 22_32.
MAPLE
# reuses code of A125134, b-file output
n := 1 :
for ndigs from 1 do
for d from 1 to 9 do
r := add(d*10^i, i=0..ndigs-1) ; # rep digit d in base 10
if isA125134(r) then
printf("%d %d\n", n, r) ;
n := n+1 ;
end if;
end do:
end do: # R. J. Mathar, Jul 19 2024
MATHEMATICA
Select[Flatten@ Table[FromDigits@ ConstantArray[k, n], {n, 6}, {k, 9}], Function[n, Length@ SelectFirst[Range[2, n - 2], Count[DigitCount[n, #], _?(# > 0 &)] == 1 &] == 0]] (* Michael De Vlieger, Jun 06 2017, Version 10 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Bernard Schott, Jun 05 2017
STATUS
approved