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A094903
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Average of 4 primes where the integer Schwarzian derivative is zero.
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0
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520, 2397, 3500, 3518, 3826, 4439, 4662, 6620, 7518, 8926, 9206, 10220, 10780, 10938, 12498, 12640, 12740, 14049, 14358, 18623, 20118, 20262, 22569, 24419, 25300, 25706, 26920, 27498, 28482, 29500, 30398, 30438, 31600, 31820, 31986
(list; graph; refs; listen; history; internal format)
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OFFSET
| 4,1
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FORMULA
| a(n) = if Sf(Prime[n])=0 then (Prime[n-3]+Prime[n-2]+Prime[n-1]+Prime[n])/2
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MATHEMATICA
| f1[n_]=Prime[n]-Prime[n-1] f2[n_]=Prime[n]-2*Prime[n-1]+Prime[n-2] f3[n_]=Prime[n]-3*Prime[n-1]+3*Prime[n-2]-Prime[n-3] sf[n_]=f3[n]/f1[n]-1.5*(f2[n]/f1[n])^2 a=Delete[Union[Table[If[sf[n]==0, (Prime[n-3]+Prime[n-2]+Prime[n-1]+Prime[n])/2, 0], {n, 4, 2004}]], 1]
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CROSSREFS
| Sequence in context: A043626 A147854 A147856 * A200427 A178269 A183588
Adjacent sequences: A094900 A094901 A094902 * A094904 A094905 A094906
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KEYWORD
| nonn
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AUTHOR
| Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Jun 15 2004
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