login
A044416
Numbers n such that string '84' occurs in the base 10 representation of n but not of n-1.
0
84, 184, 284, 384, 484, 584, 684, 784, 840, 884, 984, 1084, 1184, 1284, 1384, 1484, 1584, 1684, 1784, 1840, 1884, 1984, 2084, 2184, 2284, 2384, 2484, 2584, 2684, 2784, 2840, 2884, 2984, 3084, 3184, 3284, 3384, 3484, 3584
OFFSET
1,1
MATHEMATICA
Select[Range[4000], MemberQ[Partition[IntegerDigits[#], 2, 1], {8, 4}]&&!MemberQ[Partition[IntegerDigits[#-1], 2, 1], {8, 4}]&] (* Harvey P. Dale, Mar 14 2011 *)
Select[Range[4000], !StringFreeQ[ToString[#], "84"]&&StringFreeQ[ToString[#-1], "84"]&]
(* Zak Seidov Mar 14 2011 *)
CROSSREFS
Sequence in context: A295596 A287118 A306514 * A044797 A072589 A181113
KEYWORD
nonn,base
STATUS
approved