id:A066885 - OEIS Search Results

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(p(n)^2+1)/2, where p(n) is the n-th prime.

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7

5, 13, 25, 61, 85, 145, 181, 265, 421, 481, 685, 841, 925, 1105, 1405, 1741, 1861, 2245, 2521, 2665, 3121, 3445, 3961, 4705, 5101, 5305, 5725, 5941, 6385, 8065, 8581, 9385, 9661, 11101, 11401, 12325, 13285, 13945, 14965, 16021, 16381, 18241, 18625 (list; graph; listen)

	OFFSET	`2,1`
	COMMENT	`a(n) is the average of the numbers from 1 to p(n)^2. It's also the average of the primes in a p(n) by p(n) example of Haga's conjecture (see link below).` `If a(n) is a square c^2, then p(n) is a NSW prime (A088165) and a prime RMS number (A140480). [From Ctibor O. Zizka (ctibor.zizka(AT)seznam.cz), Aug 26 2008]`
	LINKS	`Carlos Rivera, The prime puzzles & problems connection, conjecture 26`
	MATHEMATICA	`a[n_] := (Prime[n]^2+1)/2`
	CROSSREFS	`Cf. A066883, A066886.` `Adjacent sequences: A066882 A066883 A066884 this_sequence A066886 A066887 A066888` `Sequence in context: A102724 A097117 A026373 this_sequence A057288 A107466 A098480`
	KEYWORD	`easy,nonn`
	AUTHOR	`Enoch Haga (Enokh(AT)comcast.net), Jan 22 2002`
	EXTENSIONS	`Edited by Dean Hickerson (dean(AT)math.ucdavis.edu), Jun 08 2002`

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Last modified October 7 14:39 EDT 2008. Contains 144666 sequences.

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