A066515 - OEIS

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A066515

Numbers n such that prime(n+1) + prime(n-2) = 2*prime(n-1), where prime(m) is the m-th prime.

13, 20, 60, 93, 113, 116, 141, 212, 234, 254, 262, 269, 277, 286, 292, 295, 302, 323, 353, 359, 370, 390, 408, 418, 474, 501, 543, 599, 613, 625, 715, 719, 724, 743, 820, 934, 940, 995, 999, 1017, 1099, 1120, 1264, 1300, 1313, 1401, 1415, 1419, 1423

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Equivalently, n such that f(n) = f(n-2) - f(n-1) where f is the prime gap function given by f(m) = p(m+1) - p(m).

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[ Range[ 3, 1440 ], Prime[ #+1 ]+Prime[ #-2 ]==2Prime[ #-1 ]& ]

PrimePi[#[[3]]]&/@Select[Partition[Prime[Range[1500]], 4, 1], First[#]+ Last[#]==2#[[2]]&] (* Harvey P. Dale, Apr 13 2012 *)

PROG

(PARI) { n=0; for (m=3, 10^10, if (prime(m+1) + prime(m-2) == 2*prime(m-1), write("b066515.txt", n++, " ", m); if (n==1000, return)) ) } \\ Harry J. Smith, Feb 20 2010

(PARI) isok(n) = prime(n+1) + prime(n-2) == 2*prime(n-1); \\ Michel Marcus, Jan 04 2016

CROSSREFS

Sequence in context: A164462 A132946 A278470 * A166656 A346401 A230498

Adjacent sequences: A066512 A066513 A066514 * A066516 A066517 A066518

KEYWORD

nonn

AUTHOR

Joseph L. Pe, Jan 04 2002

EXTENSIONS

Edited by Dean Hickerson, Jan 10 2002

STATUS

approved