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A109278
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Fastest increasing sequence: a(n) is a prime closest to the sum of all previous terms.
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1
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2, 2, 5, 11, 19, 41, 79, 157, 317, 631, 1259, 2521, 5039, 10079, 20161, 40343, 80669, 161333, 322669, 645329, 1290673, 2581349, 5162681, 10325369, 20650753, 41301493, 82602997, 165205981, 330411959, 660823921, 1321647869, 2643295709
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Cf. A109277 slowest increasing sequence.
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EXAMPLE
| a(1)=2, sum(1)=2; prime closest to sum is 2, hence a(2)=2, sum(2)=4; there are two primes 3 and 5 closest to sum(2), we choose the largest one, hence a(3)=5, sum(3)=7, etc.
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MATHEMATICA
| s={2}; su=2; Do[If[PrimeQ[su], a=su, pp=PrimePi[su]; prv=Prime[pp]; nxt=Prime[pp+1]; a=If[su-prv<nxt-su, prv, nxt]]; AppendTo[s, a]; Print[a]; su+=a, {i, 42}]; s
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CROSSREFS
| Cf. A109277.
Sequence in context: A005637 A104080 A078405 * A112527 A049680 A153983
Adjacent sequences: A109275 A109276 A109277 * A109279 A109280 A109281
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KEYWORD
| nonn
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AUTHOR
| Zak Seidov (zakseidov(AT)yahoo.com), Jun 25 2005
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