A039562 -id:A039562 - cp's OEIS frontend

A023742 Base 4 expansion uses each positive digit just once.

27, 30, 39, 45, 54, 57, 75, 78, 99, 108, 114, 120, 135, 141, 147, 156, 177, 180, 198, 201, 210, 216, 225, 228, 267, 270, 291, 300, 306, 312, 387, 396, 432, 450, 456, 480, 519, 525, 531, 540, 561, 564, 579, 588, 624, 705, 708, 720

Offset: 1

Olivier Gérard

By definition a subset of A039562. The number 4005, for example, is in A039562 but not in here. - R. J. Mathar, May 23 2008

Vincenzo Librandi, Table of n, a(n) for n = 1..4000

Union[ Map[ Plus@@(Array[ (4^#)&, Length[ # ], 0 ]*#)&, Flatten[ Table[ Permutations[ Join[ Range[ 4-1 ], Array[ 0&, k ] ] ], {k, 0, 2} ], 1 ] ] ]

A039567 Numbers whose base-5 representation has the same number of 0's, 2's and 4's.

Original entry on oeis.org

1, 3, 6, 8, 16, 18, 31, 33, 41, 43, 54, 70, 81, 83, 91, 93, 102, 110, 139, 147, 156, 158, 166, 168, 179, 195, 206, 208, 216, 218, 227, 235, 259, 269, 271, 273, 279, 295, 329, 345, 351, 353, 355, 365, 389, 397, 406, 408, 416, 418, 429, 445, 456, 458, 466, 468

Offset: 1

Olivier Gérard

			54 is a term since 54 in base 10 is 204 in base 5.

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

Cf. A007091, A039562, A039563, A039564, A039565, A039566.

filter:= proc(n) local L,q;
  L:= convert(n,base,5);
  nops(map(numboccur,{0,2,4},L))=1
end proc:
select(filter,[$1..1000]); # Robert Israel, Apr 09 2018

ok5Q[n_]:=Module[{dc5=DigitCount[n,5]},dc5[[2]]==dc5[[4]]==dc5[[5]]]; Select[Range[500],ok5Q]  (* Harvey P. Dale, Mar 05 2011 *)

cp's OEIS Frontend

A023742 Base 4 expansion uses each positive digit just once.

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