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A167180 a(n) = pi(n) plus the number of nonprimes less than prime(n). 1
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
FORMULA
a(n) = A000720(n) + A014689(n).
MAPLE
A000720 := proc(n) numtheory[pi](n) ; end proc:
A014689 := proc(n) ithprime(n) -n ; end proc:
A167180 := proc(n) A000720(n)+A014689(n) ; end proc: seq(A167180(n), n=1..120) ; # R. J. Mathar, May 21 2010
MATHEMATICA
Table[PrimePi[n] + Prime[n] - n , {n, 1, 20}] (* G. C. Greubel, Jun 04 2016 *)
CROSSREFS
Sequence in context: A024618 A089221 A347877 * A091271 A063985 A050052
KEYWORD
nonn
AUTHOR
EXTENSIONS
Corrected (89 replaced with 88, 94 with 93, 127 with 126, 146 with 145, etc.) by R. J. Mathar, May 21 2010
STATUS
approved

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Last modified March 28 16:58 EDT 2024. Contains 371254 sequences. (Running on oeis4.)