A043949 - OEIS

A043949

Numbers k such that 2 and 7 occur juxtaposed in the base-8 representation of k but not of k+1.

23, 58, 87, 122, 151, 191, 215, 250, 279, 314, 343, 378, 407, 442, 471, 506, 535, 570, 599, 634, 663, 703, 727, 762, 791, 826, 855, 890, 919, 954, 983, 1018, 1047, 1082, 1111, 1146, 1175, 1215, 1239, 1274, 1303, 1338, 1367

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..43.

MATHEMATICA

s27Q[n_]:=Module[{idn8=IntegerDigits[n, 8]}, If[SequenceCount[idn8, {2, 7}]> 0 ||SequenceCount[idn8, {7, 2}]>0, 1, 0]]; Transpose[ SequencePosition[ Table[ s27Q[n], {n, 1400}], {1, 0}]][[1]] (* The program uses the SequenceCount and SequencePosition functions from Mathematica version 10 *) (* Harvey P. Dale, Oct 10 2015 *)

CROSSREFS

Cf. A007094.

Sequence in context: A153353 A039346 A043169 * A005111 A225550 A179629

Adjacent sequences: A043946 A043947 A043948 * A043950 A043951 A043952

KEYWORD

nonn,base

AUTHOR

Clark Kimberling

STATUS

approved