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Search: id:A102770
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| A102770 |
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Half the decrement of the product of pairs of consecutive odd primes. |
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+0
1
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| 7, 17, 38, 71, 110, 161, 218, 333, 449, 573, 758, 881, 1010, 1245, 1563, 1799, 2043, 2378, 2591, 2883, 3278, 3693, 4316, 4898, 5201, 5510, 5831, 6158, 7175, 8318, 8973, 9521, 10355, 11249, 11853, 12795, 13610, 14445, 15483, 16199, 17285, 18431, 19010
(list; graph; listen)
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OFFSET
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0,1
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FORMULA
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a(n) = (opr(n)*opr(n+1)-1)/2 where opr(0) = 3, opr(1) = 5, ... (the odd primes).
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EXAMPLE
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opr(0) = 3, opr(1) = 5, so a(0) = (3*5-1)/2 = 7
opr(2) = 7, so a(1) = (5*7-1)/2 = 17
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CROSSREFS
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Cf. A000040 (primes; no entry for odd primes?).
Sequence in context: A090147 A155007 A140121 this_sequence A058273 A058274 A124965
Adjacent sequences: A102767 A102768 A102769 this_sequence A102771 A102772 A102773
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KEYWORD
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easy,nonn
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AUTHOR
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Neville Holmes (neville.holmes(AT)utas.edu.au), Feb 10 2005
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