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A126701
a(n) = number of primes <= !n, where !n is subfactorial n.
2
0, 0, 1, 4, 14, 56, 283, 1738, 12457, 102492, 951651, 9830851, 111757480, 1385739200, 18604785172, 268807211509, 4157797131788, 68538901559776, 1199382039260721, 22203590239217092, 433511971123048194, 8902234772796777434, 191798011804919907012
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OFFSET
1,4
LINKS
Table of n, a(n) for n=1..23.
Kim Walisch, Fast C++ prime counting function implementation (primecount).
FORMULA
a(n) = A000720(A000166(n)). - Jens Kruse Andersen, Jul 18 2014
EXAMPLE
a(5) = 14, because !5 = 44 and the number of primes up to 44 is 14.
CROSSREFS
Cf. A000720, A000166.
Sequence in context: A346816 A375454 A006212 * A309514 A151884 A002735
Adjacent sequences: A126698 A126699 A126700 * A126702 A126703 A126704
KEYWORD
hard,nonn
AUTHOR
Shyam Sunder Gupta, Feb 11 2007
EXTENSIONS
a(17)-a(20) from Jens Kruse Andersen, Jul 18 2014
a(21)-a(23) using Kim Walisch's primecount, from Amiram Eldar, Aug 25 2020
STATUS
approved

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Last modified October 5 08:10 EDT 2024. Contains 376531 sequences.
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