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A055233
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Composite numbers equal to the sum of the primes from their smallest prime factor to their largest prime factor.
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7
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OFFSET
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1,1
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COMMENTS
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Composite n such that n = p_1 + p_2 + ... + p_k where the p_i are consecutive primes, p_1 is the smallest prime factor of n and p_k is the largest.
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LINKS
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Table of n, a(n) for n=1..6.
Erich Friedman, What's Special About This Number?
C. Rivera, Puzzle
Robert Munafo, Notable Properties of Specific Numbers
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EXAMPLE
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10 = 2*5 = 2 + 3 + 5; 39 = 3*13 = 3 + 5 + 7 + 11 + 13; 371 = 7*53 = 7 + 11 + 13 + ... + 53.
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CROSSREFS
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Cf. A074036, A055514, A169802.
Sequence in context: A059722 A074225 A055514 * A189947 A197705 A187205
Adjacent sequences: A055230 A055231 A055232 * A055234 A055235 A055236
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KEYWORD
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nice,nonn
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AUTHOR
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Carlos B. Rivera F (crivera(AT)primepuzzles.net), Jun 21 2000
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EXTENSIONS
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a(5) found by Jud McCranie, Jul 03 2000
Concerning a(6): 454539357304421 is the product of two primes, 3536123 * 128541727 and also the sum of these two plus all the primes in between: 3536123 + 3536129 + 3536131 + ... + 128541719 + 128541727. I do not know if there are any terms in A055233 between 2935561623745 and 454539357304421. (I have searched for values of N satisfying N=Pa*Pb=Pa+...+Pb as far as 5.98*10^16, but this is not quite the same as A0055233 or A055514.) - Robert Munafo, Nov 20 2002
454539357304421 confirmed to be the 6th term by Donovan Johnson, Aug 23 2010
Example: removed last (see A055514). - Manuel Valdivia, Nov 19 2011
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STATUS
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approved
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