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URL: https://oeis.org/A371054

⇱ A371054 - OEIS

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A371054
Numbers whose ternary representation consists of a run of 1's, then a run of 0's, then a run of 2's.
1
11, 29, 35, 38, 83, 89, 107, 110, 116, 119, 245, 251, 269, 323, 326, 332, 350, 353, 359, 362, 731, 737, 755, 809, 971, 974, 980, 998, 1052, 1055, 1061, 1079, 1082, 1088, 1091, 2189, 2195, 2213, 2267, 2429, 2915, 2918, 2924, 2942, 2996, 3158, 3161, 3167, 3185
OFFSET
1,1
COMMENTS
a(n) == 2 (mod 3) for all n.
MATHEMATICA
Map[#[[1]] &, Select[Map[{#, Map[#[[1]] &, Split[IntegerDigits[#, 3]]] == {1, 0, 2}} &,
Range[2, 4000, 3]], #[[2]] &]] (* this sequence *)
ToExpression[Map[IntegerString[#, 3] &, %]] (* A371055 *)
(* Peter J. C. Moses, Mar 06 2024 *)
Take[With[{nn=6}, Flatten[Table[FromDigits[Join[PadRight[{}, z, 1], PadRight[{}, o, 0], PadRight[{}, t, 2]], 3], {z, nn}, {o, nn}, {t, nn}]]]//Sort, 50] (* Harvey P. Dale, Mar 29 2025 *)
PROG
(Python)
from itertools import count, islice
def A371054_gen(): # generator of terms
return (3**(l-a)*(3**a-1>>1)+3**b-1 for l in count(3) for a in range(1, l-1) for b in range(1, l-a))
A371054_list = list(islice(A371054_gen(), 20)) # Chai Wah Wu, Mar 20 2024
CROSSREFS
Sequence in context: A124110 A153768 A371106 * A360181 A092194 A134307
KEYWORD
nonn,base
AUTHOR
Clark Kimberling, Mar 19 2024
STATUS
approved