A044993 Numbers whose base-3 representation contains no 0's and exactly four 2's.

80, 161, 215, 233, 239, 241, 404, 458, 476, 482, 484, 620, 638, 644, 646, 692, 698, 700, 716, 718, 724, 1133, 1187, 1205, 1211, 1213, 1349, 1367, 1373, 1375, 1421, 1427, 1429, 1445, 1447, 1453, 1835, 1853, 1859, 1861, 1907

Offset

1,1

Comments

a(A000389(k)) = (161*3^(k-5)-1)/2 for k >= 5. - Robert Israel, Sep 21 2020

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

f:= proc(d) local C, c;
   C:= combinat:-choose(d, 4);
   c:=(3^(d)-1)/2;
   op(sort([seq(c+add(3^(i-1), i=t), t=C)]))
end proc:
seq(f(d), d=4..8); # Robert Israel, Sep 21 2020

Mathematica

A044993list[upto_]:=Select[Range[upto], DigitCount[#, 3, 0]==0&&DigitCount[#, 3, 2]==4&]; A044993list[3000] (* Paolo Xausa, Aug 03 2023 *)

Crossrefs

Cf. A000389, A007089.

Sequence in context: A043332 A023702 A031460 * A043486 A031496 A044331

Adjacent sequences: A044990 A044991 A044992 * A044994 A044995 A044996

Keyword

nonn,base

Author

Clark Kimberling

Status

approved