A085977 Number of 3's in decimal expansion of prime(n).

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

Offset: 1

Author

Jason Earls, Jul 06 2003

Keywords

• base
• nonn

Examples

			prime(2) = 3, so a(2)=1 and prime(345) = 2333, so a(345)=3.
		

Links

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

Crossrefs

Cf. 0's A085974, 1's A085975, 2's A085976, 4's A085978, 5's A085979, 6's A085980, 7's A085981, 8's A085982, 9's A085983.

Programs

Haskell

a085977 = count3 0 . a000040 where
   count3 c x | d == 3    = if x < 10 then c + 1 else count3 (c + 1) x'
              | otherwise = if x < 10 then c else count3 c x'
              where (x', d) = divMod x 10
-- Reinhard Zumkeller, Apr 08 2014

Mathematica

DigitCount[Prime[Range[110]],10,3] (* Harvey P. Dale, Aug 05 2019 *)