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 A079054 a(n) = -1 if the closest prime to prime(n) is prime(n-1); = 1 if the closest prime to prime(n) is prime(n+1); = 0 if prime(n-1) and prime(n+1) are equally close to prime(n). 6
 -1, 0, -1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, -1, 0, 1, -1, 1, 1, -1, 1, -1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, -1, 1, -1, 0, 1, -1, 0, 1, -1, 1, -1, 1, -1, 0, 1, 1, -1, -1, 1, -1, 1, 0, 0, 1, -1, 1, 1, -1, -1, 1, 1, -1, -1, 1, -1, 1, -1, -1, -1, 1, 0, 1, -1, -1, 1, -1, -1, 1, -1, 1, -1, 1, -1, -1, 1, 1, -1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2 COMMENTS There is no gap before 2, so we start with prime 3. LINKS N. J. A. Sloane, Table of n, a(n) for n = 2..20000 Chris Caldwell, Prime Gaps [Broken link?] Pe, J. L. Prime Gap Tug of War C. Rivera, Puzzle 271: Prime gap tug of war. FORMULA a(n) = min(1, max(-1, A001223(n-1) - A001223(n))). - Charles R Greathouse IV, Nov 16 2012 EXAMPLE prime(1) = 2 is closer to prime(2) = 3 than prime(3) = 5, so a(2) = -1. MAPLE # From N. J. A. Sloane, Mar 13 2016 a:=[]; M:=120; for n from 2 to M-1 do q:=ithprime(n); p:=prevprime(q); r:=nextprime(q); if q-p < r-q then a:=[op(a), -1]; elif q-p=r-q then a:=[op(a), 0]; else a:=[op(a), 1]; fi; od: a; MATHEMATICA Table[-Sign[Prime[n-1] - 2*Prime[n] + Prime[n+1]], {n, 2, 100}] PROG (PARI) p=2; q=3; forprime(r=5, 97, print1(sign(2*q-r-p)", "); p=q; q=r) \\ Charles R Greathouse IV, Nov 16 2012 CROSSREFS Cf. A092243 (cumulative sum, negated), A268343. Sequence in context: A254377 A285657 A182394 * A240356 A240354 A240352 Adjacent sequences:  A079051 A079052 A079053 * A079055 A079056 A079057 KEYWORD easy,sign AUTHOR Joseph L. Pe, Feb 02 2003 STATUS approved

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Last modified November 21 09:13 EST 2018. Contains 317431 sequences. (Running on oeis4.)