A044339 - OEIS

%I #11 Nov 03 2025 08:15:34

%S 107,207,307,407,507,607,707,807,907,1007,1070,1107,1207,1307,1407,

%T 1507,1607,1707,1807,1907,2007,2070,2107,2207,2307,2407,2507,2607,

%U 2707,2807,2907,3007,3070,3107,3207,3307,3407,3507,3607,3707,3807,3907,4007,4070,4107,4207,4307

%N Numbers k such that the string 0,7 occurs in the base 10 representation of k but not of k-1.

%H Paolo Xausa, <a href="/A044339/b044339.txt">Table of n, a(n) for n = 1..10000</a>

%t A044339Q[k_] := StringContainsQ[IntegerString[k], "07"] && StringFreeQ[IntegerString[k - 1], "07"];

%t Select[Range[5000], A044339Q] (* _Paolo Xausa_, Nov 03 2025 *)

%K nonn,base

%O 1,1

%A _Clark Kimberling_

%E More terms from _Paolo Xausa_, Nov 03 2025