A371057 Ternary numbers consisting of a run of 2's, then a run of 0's, then a run of 1's.

201, 2001, 2011, 2201, 20001, 20011, 20111, 22001, 22011, 22201, 200001, 200011, 200111, 201111, 220001, 220011, 220111, 222001, 222011, 222201, 2000001, 2000011, 2000111, 2001111, 2011111, 2200001, 2200011, 2200111, 2201111, 2220001, 2220011, 2220111

Offset

1,1

Comments

22011 consists of the run 22, then the run 0 then the run 11.

Links

Table of n, a(n) for n=1..32.

Mathematica

Map[#[[1]] &, Select[Map[{#, Map[#[[1]] &, Split[IntegerDigits[#, 3]]] == {2, 0, 1}} &, Range[1, 36000, 3]], #[[2]] &]]    (* A371056 *)
ToExpression[Map[IntegerString[#, 3] &, %]] (* this sequence *)
(* Peter J. C. Moses, Mar 06 2024 *)

Prog

(Python)
from itertools import count, islice
def A371057_gen(): # generator of terms
    return (10**(l-a)*((10**a-1)//9<<1)+((10**b-1)//9) for l in count(3) for a in range(1, l-1) for b in range(1, l-a))
A371057_list = list(islice(A371057_gen(), 20)) # Chai Wah Wu, Mar 30 2024

Crossrefs

Cf. A007089, A371056.

Sequence in context: A226566 A061697 A371109 * A305724 A167070 A175188

Adjacent sequences: A371054 A371055 A371056 * A371058 A371059 A371060

Keyword

nonn,base

Author

Clark Kimberling, Mar 22 2024

Status

approved