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

1,48

Links

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

Example

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

Mathematica

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

Prog

(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

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.

Sequence in context: A204429 A292560 A086137 * A171624 A032548 A030597

Adjacent sequences: A085973 A085974 A085975 * A085977 A085978 A085979

Keyword

base,nonn

Author

Jason Earls, Jul 06 2003

Status

approved