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Search: id:A050200
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| A050200 |
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Let p = prime(n). Then a(n) = p + (next prime >= p+1) + (next prime >= p+3). |
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+0
1
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| 10, 15, 23, 29, 41, 47, 59, 65, 81, 97, 105, 119, 131, 137, 153, 171, 187, 195, 209, 223, 231, 245, 261, 283, 299, 311, 317, 329, 335, 367, 389, 405, 425, 437, 457, 465, 483, 497, 513, 531, 551, 563, 581, 587, 607, 621, 657, 677, 689, 695, 711, 731, 743, 765
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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The occurrence of multiples of 3 in the sequence appears to converge to about .44
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MATHEMATICA
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nextprim[n_] := Block[{k = n}, While[ ! PrimeQ[k], k++ ]; k]; f[n_] := (x = Prime[n]; nextprim[x] + nextprim[x + 1] + nextprim[x + 3]); Table[ f[n], {n, 54}] (from Robert G. Wilson v Feb 12 2005)
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PROGRAM
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(PARI) sumprime3(n) = { c1=0; c2=0; forprime(x=2, n, s = nextprime(x)+nextprime(x+1)+nextprime(x+3); c1++; if(s%3==0, c2++); print1(s" "); ); print(); print(c2/c1+.0) }
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CROSSREFS
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Cf. A034962.
Adjacent sequences: A050197 A050198 A050199 this_sequence A050201 A050202 A050203
Sequence in context: A115679 A109373 A120138 this_sequence A034961 A117847 A057990
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KEYWORD
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easy,nonn
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AUTHOR
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Cino Hilliard (hillcino368(AT)gmail.com), May 08 2003
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EXTENSIONS
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Definition corrected by Zak Robert G. Wilson v and Ralf Stephan, Feb 10 2005
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