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 A175027 Replace prime with its index! 5
 0, 1, 1, 2, 4, 3, 6, 4, 8, 9, 10, 5, 12, 6, 14, 15, 16, 7, 18, 8, 20, 21, 22, 9, 24, 25, 26, 27, 28, 10, 30, 11, 32, 33, 34, 35, 36, 12, 38, 39, 40, 13, 42, 14, 44, 45, 46, 15, 48, 49, 50, 51, 52, 16, 54, 55, 56, 57, 58, 17, 60, 18, 62, 63, 64, 65, 66, 19, 68, 69, 70, 20, 72, 21 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS Table of n, a(n) for n=0..73. FORMULA a(n)=n if n is nonprime otherwise a(n)=primepi(n). MATHEMATICA Table[If[PrimeQ[n], PrimePi[n], n], {n, 0, 200}] CROSSREFS Cf. A068519. Sequence in context: A015049 A057956 A151734 * A269837 A308982 A182298 Adjacent sequences: A175024 A175025 A175026 * A175028 A175029 A175030 KEYWORD nonn AUTHOR Zak Seidov, Nov 04 2009 STATUS approved

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Last modified June 16 13:54 EDT 2024. Contains 373429 sequences. (Running on oeis4.)