A044519 Numbers n such that string 0,0 occurs in the base 7 representation of n but not of n+1.

49, 98, 147, 196, 245, 294, 349, 392, 441, 490, 539, 588, 637, 692, 735, 784, 833, 882, 931, 980, 1035, 1078, 1127, 1176, 1225, 1274, 1323, 1378, 1421, 1470, 1519, 1568, 1617, 1666, 1721, 1764, 1813, 1862, 1911, 1960, 2009, 2064, 2107, 2156, 2205, 2254, 2303

Offset

1,1

Links

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

Mathematica

f[n_] := Length[StringPosition[ToString[FromDigits[IntegerDigits[n, 7]]], "00", 1]]; Select[Table[n, {n, 10000}], f[#] > 0 && f[# + 1] == 0 &] (* Vladimir Joseph Stephan Orlovsky, Jul 23 2011 *)
SequencePosition[Table[If[SequenceCount[IntegerDigits[n, 7], {0, 0}]>0, 1, 0], {n, 2500}], {1, 0}][[All, 1]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jan 27 2021 *)

Crossrefs

Cf. A044138.

Sequence in context: A174386 A044138 A043394 * A031484 A260009 A114013

Adjacent sequences: A044516 A044517 A044518 * A044520 A044521 A044522

Keyword

nonn,base

Author

Clark Kimberling

Status

approved