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A076973
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Starting with 2, largest prime divisor of the sum of all previous terms.
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2
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2, 2, 2, 3, 3, 3, 5, 5, 5, 5, 7, 7, 7, 7, 7, 7, 11, 11, 11, 11, 11, 11, 13, 13, 13, 13, 13, 13, 17, 17, 17, 17, 17, 17, 19, 19, 19, 19, 19, 19, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 29, 29, 29, 29, 29, 29, 29, 29, 31, 31, 31, 31, 31, 31, 31, 31, 37, 37, 37, 37, 37, 37, 37, 37
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Conjecture: start from any initial value a(1)=m>=2 and define a(n) to be the largest prime factor of a(1)+a(2)+...+a(n-1); then a(n)=n/2+O(log(n)) and there are infinitely primes p such that a(2p)=p. - Benoit Cloitre (benoit7848c(AT)orange.fr), Jun 04 2003
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FORMULA
| a(n) = p(m) (the m-th prime), where m is the smallest index such that n <= p(m+1)+p(m)-2. [From Max Alekseyev (maxale(AT)gmail.com), Oct 21 2008]
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CROSSREFS
| From the third term onwards the sequence coincides with A076272.
Sequence in context: A184258 A029160 A032562 * A008649 A008650 A062051
Adjacent sequences: A076970 A076971 A076972 * A076974 A076975 A076976
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KEYWORD
| nonn
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AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Oct 22 2002
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EXTENSIONS
| More terms from Sascha Kurz (sascha.kurz(AT)uni-bayreuth.de), Jan 22 2003
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