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 A168048 a(n) = C(n)*Pi(n) where C(n) = number of nonprimes <= n, Pi(n) = number of primes <= n. 1
 0, 1, 2, 4, 6, 9, 12, 16, 20, 24, 30, 35, 42, 48, 54, 60, 70, 77, 88, 96, 104, 112, 126, 135, 144, 153, 162, 171, 190, 200, 220, 231, 242, 253, 264, 275, 300, 312, 324, 336, 364, 377, 406, 420, 434, 448, 480, 495, 510, 525, 540, 555, 592, 608, 624, 640, 656, 672 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS FORMULA a(n) = A062298(n)*A000720(n). MAPLE A000720 := proc(n) numtheory[pi](n) ; end proc: A168048 := proc(n) pi := A000720(n) ; pi*(n-pi) ; end proc: seq(A168048(n), n=1..120) ; # R. J. Mathar, Nov 18 2009 CROSSREFS Cf. A000720, A062298. Sequence in context: A095114 A062048 A194174 * A075354 A194164 A194254 Adjacent sequences:  A168045 A168046 A168047 * A168049 A168050 A168051 KEYWORD nonn AUTHOR Daniel Tisdale, Nov 17 2009 EXTENSIONS a(1) and terms after a(16) from R. J. Mathar, Nov 18 2009 Edited by Jon E. Schoenfield, May 10 2019 STATUS approved

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Last modified October 21 22:47 EDT 2019. Contains 328315 sequences. (Running on oeis4.)