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Search: id:A102655
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| A102655 |
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Numbers which are the arithmetic mean of four successive primes. |
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+0
6
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| 9, 12, 15, 18, 22, 30, 38, 42, 46, 55, 60, 68, 81, 87, 102, 105, 108, 114, 120, 127, 139, 144, 149, 155, 165, 175, 181, 186, 195, 200, 215, 228, 232, 241, 247, 253, 260, 265, 270, 278, 291, 306, 312, 318, 333, 341, 352, 357, 363, 381, 387, 399, 420, 426, 431
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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4*n=A000040(i)+A000040(i+1)+A000040(i+2)+A000040(i+3) for some i>=1.
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EXAMPLE
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a(1) = 9 because (5+7+11+13)/4=9;
a(2) = 12 because (7+11+13+17)/4=12;
a(3) = 15 because (11+13+17+19)/4=15.
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MATHEMATICA
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Select[ Table[ Sum[ Prime[i], {i, n, n + 3}]/4, {n, 83}], IntegerQ[ # ] &] (from Robert G. Wilson v Feb 04 2005)
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CROSSREFS
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Sequence in context: A138945 A119486 A161345 this_sequence A120167 A048699 A019468
Adjacent sequences: A102652 A102653 A102654 this_sequence A102656 A102657 A102658
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KEYWORD
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easy,nonn
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AUTHOR
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Giovanni Teofilatto (g.teofilatto(AT)tiscalinet.it), Feb 02 2005
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EXTENSIONS
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Edited by Robert G. Wilson v (rgwv(AT)rgwv.com) and Neville Holmes (neville.holmes(AT)utas.edu.au), Feb 04 2005
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