cp's OEIS Frontend

A297145 Numbers whose base-9 digits d(m), d(m-1), ..., d(0) have m=0 or else d(i) = d(i+1) for some i in {0,1,...,m-1}.

%I A297145 #11 Jan 18 2018 07:44:46
%S A297145 1,2,3,4,5,6,7,8,10,20,30,40,50,60,70,80,81,90,91,92,93,94,95,96,97,
%T A297145 98,101,111,121,131,141,151,161,162,172,180,181,182,183,184,185,186,
%U A297145 187,188,192,202,212,222,232,242,243,253,263,270,271,272,273,274
%N A297145 Numbers whose base-9 digits d(m), d(m-1), ..., d(0) have m=0 or else d(i) = d(i+1) for some i in {0,1,...,m-1}.
%C A297145 These numbers comprise the complement of the set of numbers in the union of A297142 and A297143.
%C A297145 Differs from A044820 first for 730 = 1001_9, which is in this sequence but not in A044820. - _R. J. Mathar_, Jan 18 2018
%e A297145 Base-9 digits of 9993: 1,4,6,3,3, so that 9993 is in the sequence.
%p A297145 read("transforms") :
%p A297145 isA297145 := proc(n)
%p A297145     local dgs,ud;
%p A297145     dgs := convert(n,base,9) ;
%p A297145     if nops(dgs) < 2 then
%p A297145         return true;
%p A297145     end if;
%p A297145     if 0 in DIFF(dgs) then
%p A297145         true;
%p A297145     else
%p A297145         false;
%p A297145     end if;
%p A297145 end proc:
%p A297145 for n from 1 to 300 do
%p A297145     if isA297145(n) then
%p A297145         printf("%d,",n) ;
%p A297145     end if;
%p A297145 end do: # _R. J. Mathar_, Jan 18 2018
%t A297145 a[n_, b_] := Sign[Differences[IntegerDigits[n, b]]]; z = 300;
%t A297145 b = 9; t = Table[a[n, b], {n, 1, 10*z}];
%t A297145 u = Select[Range[z], ! MemberQ[t[[#]], 0] && First[t[[#]]] == 1 &]   (* A297143 *)
%t A297145 v = Select[Range[z], ! MemberQ[t[[#]], 0] && First[t[[#]]] == -1 &]  (* A297144 *)
%t A297145 Complement[Range[z], Union[u, v]]  (* A297145 *)
%Y A297145 Cf. A297143, A297144.
%K A297145 nonn,easy,base
%O A297145 1,2
%A A297145 _Clark Kimberling_, Jan 15 2018