A074461 - OEIS

%I #8 Jan 17 2020 03:29:23

%S 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,

%T 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,

%U 4,5,3,5,5,4,6,4,6,6,1,4,4,2,2,3,5,3,5,5,3,4

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

%H Andrew Howroyd, <a href="/A074461/b074461.txt">Table of n, a(n) for n = 1..1000</a>

%F a(n) = A004426(A000040(n)). - _Reinhard Zumkeller_, May 27 2010

%e 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, ...

%o (PARI) a(n)={my(v=digits(prime(n))); vecsum(v)\#v} \\ _Andrew Howroyd_, Jan 16 2020

%Y Cf. A000040, A004426, A074462.

%K easy,nonn,base

%O 1,1

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

%E Offset corrected and terms a(21) and beyond from _Andrew Howroyd_, Jan 16 2020