OFFSET
1,1
EXAMPLE
There are 21 2-digit primes, so a(2)=2*21=42.
MATHEMATICA
Flatten[Table[n*Differences[PrimePi[{10^(n - 1), 10^n}]], {n, 13}]] (* Jayanta Basu, Jun 27 2013 *)
With[{nn=14}, Differences[PrimePi[10^Range[0, nn]]]*Range[nn]] (* This program generates only the first 14 terms of the sequence; Mathematica's PrimePi function cannot generate the 15th or higher terms *) (* Harvey P. Dale, Apr 22 2016 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
EXTENSIONS
Corrected by Jud McCranie and N. J. A. Sloane.
STATUS
approved
