A045116 Numbers whose base-4 representation contains exactly one 1 and two 3's.

31, 55, 61, 79, 111, 115, 123, 124, 126, 159, 183, 189, 199, 205, 211, 219, 220, 222, 231, 237, 241, 244, 246, 249, 271, 303, 307, 315, 316, 318, 399, 431, 435, 443, 444, 446, 451, 459, 460, 462, 483, 491, 492, 494, 496, 498

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Mathematica

b413Q[n_]:=Module[{dc=DigitCount[n, 4]}, dc[[1]]==1&&dc[[3]]==2]; Select[ Range[500], b413Q] (* Harvey P. Dale, Oct 22 2011 *)
Select[Range[500], DigitCount[#, 4, 1]==1&&DigitCount[#, 4, 3]==2&] (* Harvey P. Dale, Jan 18 2026 *)

Crossrefs

Cf. A007090.

Sequence in context: A182380 A141856 A104332 * A092227 A220539 A193362

Adjacent sequences: A045113 A045114 A045115 * A045117 A045118 A045119

Keyword

nonn,base

Author

Clark Kimberling

Status

approved