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Search: id:A114897
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| A114897 |
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a(1) = 1. a(n+1) = number of earlier terms a(k) (1 <= k <= n) where a(k)+n is a prime. |
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+0
4
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| 1, 1, 2, 1, 3, 1, 4, 1, 1, 2, 7, 2, 7, 1, 1, 4, 11, 3, 9, 2, 4, 4, 11, 0, 2, 4, 4, 11, 11, 6, 14, 2, 5, 7, 6, 8, 16, 10, 4, 15, 13, 9, 13, 10, 5, 9, 14, 5, 9, 9, 11, 10, 17, 6, 9, 11, 13, 19, 20, 11, 22, 8, 17, 14, 13, 14, 20, 13, 13, 22, 23, 9, 20, 8, 12, 16, 11, 13, 21, 13, 13, 16, 14, 12
(list; graph; listen)
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OFFSET
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1,3
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..2000
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FORMULA
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a(n) = A123541(n-1) for n>3. - T. D. Noe, Apr 29 2007
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EXAMPLE
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If we add 10 to each of the first 10 terms of the sequence, we get
[11,11,12,11,13,11,14,11,11,12]. Of these only the six 11's and the 13 are primes. So a(11) = 7.
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PROGRAM
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(PARI) {v=[1]; for(n=2, 250, w=vector(length(v)+1); s=0; for(i=1, length(v), w[i]=v[i]; if(isprime(v[i]+n-1), s++)); w[length(v)+1]=s; v=w); v} (Herrgesell)
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CROSSREFS
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Cf. A108839.
Sequence in context: A081386 A143802 A135591 this_sequence A123539 A142593 A102547
Adjacent sequences: A114894 A114895 A114896 this_sequence A114898 A114899 A114900
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KEYWORD
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nonn,nice
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AUTHOR
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Leroy Quet (qq-quet(AT)mindspring.com), Jan 05 2006
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EXTENSIONS
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More terms from Lambert Herrgesell (zero815(AT)googlemail.com), Jan 16 2006
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