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A043095
Numbers with property that no two consecutive base 9 digits are equal.
4
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 24, 25, 26, 27, 28, 29, 31, 32, 33, 34, 35, 36, 37, 38, 39, 41, 42, 43, 44, 45, 46, 47, 48, 49, 51, 52, 53, 54, 55, 56, 57, 58, 59, 61, 62, 63, 64, 65, 66, 67, 68, 69, 71, 72, 73, 74, 75, 76, 77, 78, 79, 82
OFFSET
1,3
LINKS
MAPLE
isA043095 := proc(n)
dgs := convert(n, base, 9) ;
for i from 2 to nops(dgs) do
if op(i, dgs) = op(i-1, dgs) then
return false;
end if;
end do:
true ;
end proc:
A043095 := proc(n)
option remember;
if n =1 then
0;
else
for a from procname(n-1)+1 do
if isA043095(a) then
return a;
end if;
end do;
end if;
end proc:
seq(A043095(n), n=1..120) ; # R. J. Mathar, Dec 28 2023
MATHEMATICA
Select[Range[0, 100], !MemberQ[Flatten[Differences/@Partition[ IntegerDigits[ #, 9], 2, 1]], 0]&] (* Harvey P. Dale, Apr 05 2014 *)
PROG
(PARI) isok(n) = {my(d = digits(n, 9)); for (i=2, #d, if (d[i] == d[i-1], return (0)); ); return (1); } \\ Michel Marcus, Oct 11 2017
CROSSREFS
Cf. A000975 (base-2 analog), A031941 or A043089 (base-3 analog), A031942 or A043090 (base-4 analog), A031943 or A043091 (base-5 analog), A043092, ..., A043096 (base-6 through base-10 analog).
Sequence in context: A209931 A052382 A367733 * A055572 A052040 A328781
KEYWORD
nonn,base
STATUS
approved