A226273 Number of distinct values u^v, where u and v are digits occurring in decimal representation of n.

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 4, 3, 4, 4, 4, 4, 4, 3, 3, 4, 1, 4, 4, 4, 4, 4, 4, 3, 3, 3, 4, 1, 4, 4, 4, 4, 4, 3, 3, 4, 4, 4, 1, 4, 4, 4, 4, 3, 3, 4, 4, 4, 4, 1, 4, 4, 4, 3, 3, 4, 4, 4, 4, 4, 1, 4, 4, 3, 3, 4, 4, 4, 4

Offset: 0

Author

Reinhard Zumkeller, Jul 09 2013

Keywords

• nonn
• base

Comments

Row lengths in table A226272;

a(n) <= 61; A171102(1) = 1023456789 is the smallest number m such that a(m) = 61.

a(n) = 61 for almost all n, in the sense that the natural density of n such that a(n) < 61 is 0. - Charles R Greathouse IV, May 13 2015

Examples

			See A226272.
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 0..1000

Programs

Haskell

a226273 = length . a226272_row :: Integer -> Int

PARI

a(n)=if(n<9, return(1)); my(d=Set(digits(n)),v=List()); for(i=1,#d, for(j=1,#d, listput(v,d[i]^d[j]))); #Set(v) \\ Charles R Greathouse IV, May 13 2015