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Search: id:A049529
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| A049529 |
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Numbers n such that sum of factorials of digits of n equals pi(n) (A000720). |
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+0
4
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| 6500, 6501, 6510, 6511, 6521, 12066, 50372, 175677, 553783, 5224903, 5224923, 5246963, 5302479, 5854093, 5854409, 5854419, 5854429, 5854493, 5855904, 5864049, 5865393, 10990544, 11071599
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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By the time that n = 10^8 the number of primes <= 10^8 (5761455) exceeds 8*9! (2903040). - Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 16 2002
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LINKS
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C. Caldwell and G. L. Honaker, Jr., Is pi(6521)=6!+5!+2!+1! unique?, Math. Spectrum, 22:2 (2000/2001) 34-36.
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
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EXAMPLE
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a(10)=5224903 because there are exactly 5!+2!+2!+4!+9!+0!+3! (or 363035) prime numbers less than or equal to 5224903.
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MATHEMATICA
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Do[ If[ Apply[ Plus, IntegerDigits[n] ! ] == PrimePi[n], Print[n]], {n, 1, 11100000} ]
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CROSSREFS
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Cf. A000720, A049530.
Sequence in context: A104242 A031842 A028544 this_sequence A156416 A156418 A068270
Adjacent sequences: A049526 A049527 A049528 this_sequence A049530 A049531 A049532
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KEYWORD
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fini,full,nonn,base
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AUTHOR
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G. L. Honaker, Jr. (honak3r(AT)gmail.com), Sep 15 1999.
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