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 A065899 Which composite number is A036691(n), the n-th compositorial number, the product of first n composite number? 1
 1, 14, 148, 1458, 15293, 188782, 2692726, 40909988, 660637057, 11976280879, 240871231369, 5080851687840, 112183659405198, 2700581280109040, 67686358108129808, 1763651979163805444, 47707175694652299653, 1337959106215345951164, 40196133912310028013721, 1287910861213828031657392 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS FORMULA a(n) = A036691(n) - primepi(A036691(n))-1. a(n) = A065855(A036691(n)). - Chai Wah Wu, Sep 08 2020 EXAMPLE a(2) = 14 because 4*6 = 24, the 2nd compositorial number is the 14th composite number: 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24. MATHEMATICA Table[A036691[n]-(PrimePi[A036691[n]])-1, {n, 1, 9}] Composite[n_] := FixedPoint[n + PrimePi[ # ] + 1 &, n + PrimePi[n] + 1]; Table[c = Product[ Composite[i], {i, 1, n} ]; c - PrimePi[c] - 1, {n, 1, 10} ] PROG (Python) from sympy import factorial, primepi, composite, primorial, compositepi def A065899(n):     return compositepi(factorial(composite(n))//primorial(primepi(composite(n)))) # Chai Wah Wu, Sep 08 2020 CROSSREFS Cf. A002808, A000720, A036691, A065855. Sequence in context: A207259 A016170 A081201 * A162965 A067103 A081184 Adjacent sequences:  A065896 A065897 A065898 * A065900 A065901 A065902 KEYWORD nonn AUTHOR Labos Elemer, Nov 28 2001 EXTENSIONS One more term from Robert G. Wilson v, Nov 29 2001 a(11)-a(19) from Chai Wah Wu, Sep 08 2020 a(20) from Chai Wah Wu, Sep 09 2020 STATUS approved

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Last modified May 7 10:18 EDT 2021. Contains 343650 sequences. (Running on oeis4.)