A044250 - OEIS

A044250

Numbers n such that string 7,7 occurs in the base 8 representation of n but not of n-1.

%I #10 Feb 23 2014 14:07:14

%S 63,127,191,255,319,383,447,504,575,639,703,767,831,895,959,1016,1087,

%T 1151,1215,1279,1343,1407,1471,1528,1599,1663,1727,1791,1855,1919,

%U 1983,2040,2111,2175,2239,2303,2367,2431,2495,2552

%N Numbers n such that string 7,7 occurs in the base 8 representation of n but not of n-1.

%H Vincenzo Librandi, <a href="/A044250/b044250.txt">Table of n, a(n) for n = 1..2000</a>

%t Select[Range[3000],MemberQ[Partition[IntegerDigits[#,8],2,1],{7,7}] && !MemberQ[Partition[IntegerDigits[#-1,8],2,1],{7,7}]&] (* _Harvey P. Dale_, Feb 22 2014 *)

%K nonn,base

%O 1,1

%A _Clark Kimberling_