A085976 Number of 2's in decimal expansion of prime(n).

1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0

Offset: 1

Author

Jason Earls, Jul 06 2003

Keywords

• base
• nonn

Examples

			prime(4) = 7, so a(4)=0 and prime(2490) = 22229, so a(2490)=4.
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. 0's A085974, 1's A085975, 3's A085977, 4's A085978, 5's A085979, 6's A085980, 7's A085981, 8's A085982, 9's A085983.

Programs

Haskell

a085976 = count2 0 . a000040 where
   count2 c x | d == 2    = if x < 10 then c + 1 else count2 (c + 1) x'
              | otherwise = if x < 10 then c else count2 c x'
              where (x', d) = divMod x 10
-- Reinhard Zumkeller, Apr 08 2014

Mathematica

DigitCount[Prime[Range[110]],10,2] (* Harvey P. Dale, Jan 14 2014 *)