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

1,1

Comments

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

Links

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

Mathematica

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

Crossrefs

Sequence in context: A214832 A090043 A030491 * A039562 A160394 A316729

Adjacent sequences: A023739 A023740 A023741 * A023743 A023744 A023745

Keyword

nonn,base,easy

Author

Olivier Gérard

Status

approved