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Search: id:A079834
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| A079834 |
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Define f(n)= n + tau(n), then a(n) = k where k is the number of steps required to get the smallest prime of the form f(f(f...f(n)))). |
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| 1, 2, 1, 1, 1, 11, 11, 10, 10, 10, 1, 9, 2, 9, 1, 10, 1, 8, 10, 8, 9, 8, 9, 7, 8, 7, 1, 7, 1, 6, 2, 6, 1, 6, 2, 4, 2, 5, 1, 95, 1, 4, 4, 4, 3, 4, 96, 94, 95, 3, 2, 94, 2, 93, 1, 2, 1, 93, 1, 9, 3, 92, 2, 1, 2, 91, 2, 91, 1, 90, 1, 8, 91, 90, 90, 90, 90, 89, 90, 88, 89, 89, 2, 7, 1, 88, 5, 7, 5, 87, 4
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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a(6) = 11 as f(6) = 10, f(10) = 14, f(14) = 18, f(18) = 24, f(24) = 32, f(32) = 38, f(38) = 42, f(42) = 50, f(50) = 56, f(56) = 64, f(64) = 64 +7 = 71.
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PROGRAM
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(PARI) { a(n) = local(k, m); k=1; m=n; while(1, m=m+numdiv(m); if(isprime(m), return(k)); k++ ) } (Alekseyev)
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CROSSREFS
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Cf. A079833.
Adjacent sequences: A079831 A079832 A079833 this_sequence A079835 A079836 A079837
Sequence in context: A007737 A105688 A066017 this_sequence A029582 A067095 A070888
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Feb 12 2003
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EXTENSIONS
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More terms from Max Alekseyev (maxal(AT)cs.ucsd.edu), Apr 19 2005
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