A074462 Average digit (rounded up) in the decimal expansion of prime(n).

2, 3, 5, 7, 1, 2, 4, 5, 3, 6, 2, 5, 3, 4, 6, 4, 7, 4, 7, 4, 5, 8, 6, 9, 8, 1, 2, 3, 4, 2, 4, 2, 4, 5, 5, 3, 5, 4, 5, 4, 6, 4, 4, 5, 6, 7, 2, 3, 4, 5, 3, 5, 3, 3, 5, 4, 6, 4, 6, 4, 5, 5, 4, 2, 3, 4, 3, 5, 5, 6, 4, 6, 6, 5, 7, 5, 7, 7, 2, 5, 5, 3, 3, 4, 6, 4, 6, 6, 4, 5, 6, 7, 7, 5, 8, 3, 5, 3, 4, 4, 6, 6, 5, 7, 5, 7, 7, 6, 8, 3, 5, 4, 5, 6, 4, 4, 5, 6, 5, 7

Offset: 1

Author

Y. Kelly Itakura (yitkr(AT)mta.ca), Aug 23 2002

Keywords

• easy
• nonn
• base

Examples

			The prime numbers begin with 2,3,5,7,11,13,17,19,23,... so the average digits rounded up are 2, 3, 5, 7, (1+1)/2=1, (1+3)/2=2, (1+7)/2=4, (1+9)/2=5, ceiling((2+3)/2)=3, ...
		

Crossrefs

Cf. A000040, A004427, A074461, A073342.

Cf. A007605, A097944.

Programs

Mathematica

Table[Ceiling[Mean[IntegerDigits[p]]],{p,Prime[Range[120]]}] (* Harvey P. Dale, Nov 06 2022 *)

PARI

a(n) = my(d=digits(prime(n))); ceil(vecsum(d)/#d); \\ Michel Marcus, Apr 23 2022

Formula

a(n) = ceiling(A007605(n)/A097944(n)). - R. J. Mathar, Sep 23 2008

a(n) = A004427(A000040(n)). - Reinhard Zumkeller, May 27 2010

Extensions

Offset changed to 1, cf. to A073342 added, and extended by R. J. Mathar, Sep 23 2008