Invitation: celebrating 50 years of OEIS, 250000 sequences, and Sloane's 75th, there will be a conference at DIMACS, Rutgers, Oct 9-10 2014.
1,2
Complement of set {A(prime(n)+n)} = {A014688(n)} = {A(A000040(n)+A000027(n))}. [From Jaroslav Krizek, Dec 10 2009]
a(n) = numbers m such that are not the sum of k-th prime and k for any k >= 1. [From Jaroslav Krizek, Dec 10 2009]
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Prime Counting Function
Wikipedia, Prime-counting function
For n > 1: a(n) = A000720(n - 1) + n.
a[n_] := PrimePi[a[n-1]]+n; a[1]=1
(Haskell)
a064427 1 = 1
a064427 n = a000720 (n - 1) + toInteger n
-- Reinhard Zumkeller, Apr 17 2012
Cf. A095117.
Sequence in context: A026516 A186493 A111094 * A183569 A247000 A213356
Adjacent sequences: A064424 A064425 A064426 * A064428 A064429 A064430
nonn
Santi Spadaro, Sep 30 2001
Definition improved by Reinhard Zumkeller, Apr 16 2012
approved