login
A023742
Base 4 expansion uses each positive digit just once.
1
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
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
KEYWORD
nonn,base,easy
STATUS
approved