login
A045238
Numbers whose base-5 representation contains exactly one 1 and two 3's.
1
43, 83, 91, 143, 193, 203, 213, 215, 217, 219, 223, 243, 293, 333, 341, 383, 391, 403, 413, 415, 417, 419, 423, 433, 441, 451, 455, 457, 459, 461, 471, 483, 491, 543, 583, 591, 643, 693, 703, 713, 715, 717, 719, 723, 743, 893
OFFSET
1,1
LINKS
MAPLE
A0[1]:= {2, 4}:
A1[1]:= {1}:
A3[1]:= {3}:
A13[1]:= {}:
A33[1]:= {}:
A133[1]:= {}:
count:= 0:
for n from 2 while count < 1000 do
A0[n]:= map(t -> (5*t, 5*t+2, 5*t+4), A0[n-1]);
A1[n]:= map(t -> (5*t, 5*t+2, 5*t+4), A1[n-1]) union map(t -> 5*t+1, A0[n-1]);
A3[n]:= map(t -> (5*t, 5*t+2, 5*t+4), A3[n-1]) union map(t -> 5*t+3, A0[n-1]);
A13[n]:= map(t -> (5*t, 5*t+2, 5*t+4), A13[n-1]) union map(t -> 5*t+1, A3[n-1]) union map(t -> 5*t+3, A1[n-1]);
A33[n]:= map(t -> (5*t, 5*t+2, 5*t+4), A33[n-1]) union map(t -> 5*t+3, A3[n-1]);
A133[n]:= map(t -> (5*t, 5*t+2, 5*t+4), A133[n-1]) union map(t -> 5*t+1, A33[n-1]) union map(t -> 5*t+3, A13[n-1]);
count:= count + nops(A133[n]);
od:
sort([seq(op(A133[i]), i=1..n-1)]); # Robert Israel, Dec 10 2023
MATHEMATICA
Select[Range[900], DigitCount[#, 5, 1]==1&&DigitCount[#, 5, 3]==2&] (* Harvey P. Dale, Dec 16 2017 *)
CROSSREFS
Cf. A007091.
Sequence in context: A236839 A183074 A289730 * A139982 A171252 A119487
KEYWORD
nonn,base
STATUS
approved