A045128 Numbers whose base-4 representation contains exactly three 1's and four 3's.

5631, 6015, 6111, 6135, 6141, 7551, 7647, 7671, 7677, 8031, 8055, 8061, 8151, 8157, 8181, 13695, 13791, 13815, 13821, 14175, 14199, 14205, 14295, 14301, 14325, 15711, 15735, 15741, 15831, 15837, 15861, 16215, 16221

Offset

1,1

Links

Table of n, a(n) for n=1..33.

Mathematica

Reap[For[n=1, n<20000, n++, If[MatchQ[IntegerDigits[n, 4] // Tally // Sort, {___, {1, 3}, ___, {3, 4}}], Sow[n]]]][[2, 1]] (* Jean-François Alcover, Dec 07 2016 *)

Crossrefs

Cf. A007090.

Sequence in context: A014799 A031573 A031753 * A229591 A161193 A022010

Adjacent sequences: A045125 A045126 A045127 * A045129 A045130 A045131

Keyword

nonn,base

Author

Clark Kimberling

Status

approved