OFFSET
0,3
COMMENTS
Only because of the case n = 2 is it necessary to say "<=", otherwise "<" would suffice. Except for the first two terms, there are no consecutive identical terms for n < 10000. A065382 gives differences between consecutive terms of this sequence. - Alonso del Arte, Oct 31 2005
LINKS
Harry J. Smith, Table of n, a(n) for n = 0..10000
MATHEMATICA
Table[PrimePi[n*(n + 1)/2], {n, 0, 60}] (* Ray Chandler, Oct 31 2005 *)
PROG
(PARI) { allocatemem(932245000); default(primelimit, 4294965247); write("b111208.txt", 0, " ", 0); for (n = 1, 10000, t=n*(n + 1)/2; a=primepi(t); write("b111208.txt", n, " ", a); ) } \\ Harry J. Smith, Mar 10 2009
(Sage) [prime_pi(binomial(n, 2)) for n in range(1, 63)] # Zerinvary Lajos, Jun 06 2009
(Haskell)
a111208 n = length $ takeWhile (<= a000217 n) a000040_list
-- Reinhard Zumkeller, Nov 01
CROSSREFS
KEYWORD
nonn
AUTHOR
Giovanni Teofilatto, Oct 25 2005
EXTENSIONS
Extended by Ray Chandler and Alonso del Arte, Oct 31 2005
STATUS
approved