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A073699 Floor((Product of composite numbers up to n)/(product of primes up to n)). 1
1, 0, 0, 0, 0, 0, 0, 0, 8, 82, 7, 89, 6, 96, 1450, 23201, 1364, 24565, 1292, 25858, 543035, 11946780, 519425, 12466205, 311655142, 8103033711, 218781910200, 6125893485615, 211237706400, 6337131192016, 204423586839, 6541554778855 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,9

COMMENTS

Note 1 is neither prime nor composite.

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..644

EXAMPLE

a(10) = Floor((4*6*8*9*10)/(2*3*5*7)) = 82.

MAPLE

a := 1:b := 1:for i from 2 to 100 do if isprime(i) then a := a*i: else b := b*i:fi: c[i] := floor(b/a):od:c[1] := 1:seq(c[j], j=1..100);

MATHEMATICA

Table[t1 = Select[x = Range[n], PrimeQ]; Floor[Divide @@ Times @@@ {Complement[x, t1], t1}], {n, 32}] (* Jayanta Basu, Jul 06 2013 *)

Module[{upto=40, pr, cm}, pr=Prime[Range[PrimePi[upto]]]; cm=Select[ Range[ upto], CompositeQ]; Table[ Floor[Times@@Select[cm, #<=n&]/ Times@@ Select[ pr, #<=n&]], {n, upto}]] (* Harvey P. Dale, Nov 03 2016 *)

CROSSREFS

Sequence in context: A100879 A080811 A249898 * A163191 A241708 A317119

Adjacent sequences:  A073696 A073697 A073698 * A073700 A073701 A073702

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Aug 12 2002

EXTENSIONS

More terms from Sascha Kurz, Aug 15 2002

STATUS

approved

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Last modified October 18 22:20 EDT 2019. Contains 328211 sequences. (Running on oeis4.)