A043900 Numbers k such that 0 and 5 occur juxtaposed in the base-6 representation of k but not of k+1.

30, 41, 66, 77, 102, 113, 138, 149, 174, 185, 210, 221, 251, 257, 282, 293, 318, 329, 354, 365, 390, 401, 426, 437, 467, 473, 498, 509, 534, 545, 570, 581, 606, 617, 642, 653, 683, 689, 714, 725, 750, 761, 786, 797, 822, 833

Offset

1,1

Links

Table of n, a(n) for n=1..46.

Example

30(10) = 50(6) but 31(10) = 51(6), so 30 is in the sequence.

Mathematica

Transpose[SequencePosition[Table[If[SequenceCount[IntegerDigits[n, 6], {0, 5}]>0||SequenceCount[IntegerDigits[n, 6], {5, 0}]>0, 1, 0], {n, 1000}], {1, 0}]][[1]] (* The program uses the SequencePosition and SequenceCount functions from Mathematica version 10 *) (* Harvey P. Dale, Jan 14 2016 *)

Prog

(Sage)
@cached_function
def str_base6(x):
    return ''.join(str(y) for y in x.digits(base=6))
[x for x in [1..2000] if '50' in str_base6(x) or '05' in str_base6(x) and not('50' in str_base6(x + 1) or '05' in str_base6(x + 1))]
# Tom Edgar, May 13 2014

Crossrefs

Cf. A007092.

Sequence in context: A225049 A043120 A039297 * A103098 A110849 A074696

Adjacent sequences: A043897 A043898 A043899 * A043901 A043902 A043903

Keyword

nonn,base

Author

Clark Kimberling, Dec 11 1999

Status

approved