

A129112


Decimal expansion of constant equal to concatenated semiprimes.


0



4, 6, 9, 1, 0, 1, 4, 1, 5, 2, 1, 2, 2, 2, 5, 2, 6, 3, 3, 3, 4, 3, 5, 3, 8, 3, 9, 4, 6, 4, 9, 5, 1, 5, 5, 5, 7, 5, 8, 6, 2, 6, 5, 6, 9, 7, 4, 7, 7, 8, 2, 8, 5, 8, 6, 8, 7, 9, 1, 9, 3, 9, 4, 9, 5, 1, 0, 6, 1, 1, 1, 1, 1, 5, 1, 1, 8, 1, 1, 9, 1, 2, 1, 1, 2, 2, 1, 2, 3, 1, 2, 9
(list;
constant;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

Is this, as Copeland and Erdos (1946) showed for the CopelandErdos constant, a normal number in base 10? I conjecture that it is, despite the fact that the density of odd semiprimes exceeds the density of even semiprimes. What are the first few digits of the continued fraction of this constant? What are the positions of the first occurrence of n in the continued fraction? What are the incrementally largest terms and at what positions do they occur?
Coincides up to n=15 with concatenation of A046368.  M. F. Hasler, Oct 01 2007
Indeed, a theorem of Copeland & Erdős proves that this constant is 10normal.  Charles R Greathouse IV, Feb 06 2015


LINKS



EXAMPLE

4.691014152122252633343538394649515557586265...


MATHEMATICA

Flatten[IntegerDigits/@Select[Range[200], PrimeOmega[#]==2&]] (* Harvey P. Dale, Jan 17 2012 *)


PROG

(PARI) print1(4); for(n=6, 129, if(bigomega(n)==2, d=digits(n); for(i=1, #d, print1(", "d[i])))) \\ Charles R Greathouse IV, Feb 06 2015


CROSSREFS



KEYWORD



AUTHOR



STATUS

approved



