A180693 Smallest power of 13 that begins with n.

1, 2197, 371293, 4826809, 51185893014090757, 62748517, 7056410014866816666030739693, 815730721, 91733330193268616658399616009, 10604499373, 112455406951957393129, 12646218552730347184269489080961456410641, 13, 1461920290375446110677, 15502932802662396215269535105521

Offset: 1

Author

Daniel Mondot, Sep 18 2010

Keywords

• base
• nonn

Links

• Robert Israel, Table of n, a(n) for n = 1..99

Crossrefs

Cf. A180691, A180694, A180695.

Programs

Maple

count:= 1:
A[1]:= 1:
for n from 1 while count < 99 do
x:= 13^n;
m:= ilog10(x);
for d from 0 to 1 do
   y:= floor(x/10^(m-d));
   if not assigned(A[y]) then
     count:= count+1;
     A[y]:= x;
   fi
od
od:
seq(A[i],i=1..99); # Robert Israel, Jan 17 2016

Formula

a(n) = 13^A180694(n). - Michel Marcus, Jan 18 2016