The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A043880 Numbers k such that 0 and 1 occur juxtaposed in the base-4 representation of k but not of k+1. 2
 4, 20, 33, 36, 49, 52, 84, 97, 100, 113, 116, 129, 135, 148, 161, 164, 177, 180, 193, 199, 212, 225, 228, 241, 244, 340, 353, 356, 369, 372, 385, 391, 404, 417, 420, 433, 436, 449, 455, 468, 481, 484, 497, 500, 513, 519, 543, 545, 548, 561, 564, 596, 609, 612 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..54. MATHEMATICA SequencePosition[Table[If[SequenceCount[IntegerDigits[n, 4], {0, 1}]>0 || SequenceCount[ IntegerDigits[ n, 4], {1, 0}]>0, 1, 0], {n, 600}], {1, 0}][[All, 1]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Sep 14 2016 *) PROG (Python) from sympy.ntheory.factor_ import digits def has01or10(k): s = "".join(map(str, digits(k, 4)[1:])); return "01" in s or "10" in s def ok(n): return has01or10(n) and not has01or10(n+1) print(list(filter(ok, range(613)))) # Michael S. Branicky, Apr 20 2021 CROSSREFS Cf. A007090, A044446. Sequence in context: A205670 A115428 A172624 * A030002 A238764 A085805 Adjacent sequences: A043877 A043878 A043879 * A043881 A043882 A043883 KEYWORD nonn,base AUTHOR Clark Kimberling STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 7 20:21 EDT 2024. Contains 375749 sequences. (Running on oeis4.)