A167180 - OEIS

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A167180

a(n) = pi(n) plus the number of nonprimes less than prime(n).

1, 2, 4, 5, 9, 10, 14, 15, 18, 23, 25, 30, 34, 35, 38, 43, 49, 50, 56, 59, 60, 65, 69, 74, 81, 84, 85, 88, 90, 93, 107, 110, 115, 116, 125, 126, 132, 137, 140, 145, 151, 152, 162, 163, 166, 167, 179, 190, 193, 194, 197, 202, 204, 213, 218, 223, 228, 229, 235, 238, 240

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

The number of primes less than n plus the number of nonprimes less than the n-th prime.

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = A000720(n) + A014689(n).

MAPLE

A000720 := proc(n) numtheory[pi](n) ; end proc:

A014689 := proc(n) ithprime(n) -n ; end proc: