110 people attended OEIS-50 (videos, suggestions); annual fundraising drive to start soon (donate); editors, please edit! (stack is over 300), your editing is more valuable than any donation.
1,1
Table of n, a(n) for n=1..58.
a(n) = PrimePi(A030432(n-1)).
Select[Range[240], Mod[Prime[ # ], 10] == 7 &] (*Chandler*)
Cf. A030432, A102342.
Sequence in context: A085048 A024813 A244741 * A026360 A237514 A047535
Adjacent sequences: A049506 A049507 A049508 * A049510 A049511 A049512
nonn
N. J. A. Sloane.
Extended by Ray Chandler, Nov 07 2006
approved