A074461 - OEIS

A074461

Average digit (rounded down) in the decimal expansion of the n-th prime number.

2, 3, 5, 7, 1, 2, 4, 5, 2, 5, 2, 5, 2, 3, 5, 4, 7, 3, 6, 4, 5, 8, 5, 8, 8, 0, 1, 2, 3, 1, 3, 1, 3, 4, 4, 2, 4, 3, 4, 3, 5, 3, 3, 4, 5, 6, 1, 2, 3, 4, 2, 4, 2, 2, 4, 3, 5, 3, 5, 3, 4, 4, 3, 1, 2, 3, 2, 4, 4, 5, 3, 5, 5, 4, 6, 4, 6, 6, 1, 4, 4, 2, 2, 3, 5, 3, 5, 5, 3, 4

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Andrew Howroyd, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = A004426(A000040(n)). - Reinhard Zumkeller, May 27 2010

EXAMPLE

prime numbers: 2, 3, 5, 7, 11, 13, 17, 19, 23, ... so the average digits rounded down are; 2, 3, 5, 7, (1+1)/2 = 1, (1+3)/2 = 2, (1+7)/2 = 4, (1+9)/2 = 5, floor((2+3)/2) = 2, ...

PROG

(PARI) a(n)={my(v=digits(prime(n))); vecsum(v)\#v} \\ Andrew Howroyd, Jan 16 2020

CROSSREFS

Cf. A000040, A004426, A074462.

Sequence in context: A065859 A258062 A117819 * A285095 A073342 A074462

Adjacent sequences: A074458 A074459 A074460 * A074462 A074463 A074464

KEYWORD

easy,nonn,base

AUTHOR

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

EXTENSIONS

Offset corrected and terms a(21) and beyond from Andrew Howroyd, Jan 16 2020

STATUS

approved