login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Continued fraction of sum(prime(n)/10^b(n)), where b(n) = 1 + the total number of digits of the first n-1 primes, A068670.
0

%I #9 Oct 18 2013 04:49:05

%S 0,4,4,6,2,5,18,1,3,4,1,2,1,2,4,7,4,1,21,2,1,3,5,2,1,1,27,1,1,5,12,1,

%T 18,1,1,1,1,1,1,9,3,1,1,1,5,1,5,2,2,1,53,1,8,1,23,6,2,2,1,1,3,1,1,25,

%U 2,2,7,1,2,3,1,4,3,12,1,2,7,1,68,1,19,1,2,2,14,4,6,2,1,2,58,2,16,1,1,1,2,2,1

%N Continued fraction of sum(prime(n)/10^b(n)), where b(n) = 1 + the total number of digits of the first n-1 primes, A068670.

%F r = sum_{n=1..infinity} prime(n)/10^b(n), where b(n+1)=b(n)+floor(log[10] prime(n))+1, b(1)=1. (Edited by _M. F. Hasler_, Oct 17 2013)

%e r=0.235811317192329313741434753596167717...

%e = 2/10^1 + 3/10^2 + 5/10^3 + 7/10^4 + 11/10^5 + 13/10^7 + ..., the exponents being increased by the length of the previous prime. - _M. F. Hasler_, Oct 17 2013

%t (* number of powers of ten in the Primes as a sequence*) byte[n_Integer?Positive] := byte[n] =byte[n-1]+Floor[Log[Prime[n-1]]/Log[10]]+1 byte[0]=byte[1] = 1 b=Table[N[Prime[n]*10^(-byte[n]), Digits], {n, 1, Digits}] r=Apply[Plus, b]

%K nonn,base,cofr

%O 1,2

%A _Roger L. Bagula_, Aug 26 2003

%E Edited by _M. F. Hasler_, Oct 17 2013