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A102552 a(n) = prime(n)-(prime(n+1)+prime(n-1))/2. 2
0, -1, 1, -1, 1, -1, -1, 2, -2, 1, 1, -1, -1, 0, 2, -2, 1, 1, -2, 1, -1, -1, 2, 1, -1, 1, -1, -5, 5, -1, 2, -4, 4, -2, 0, 1, -1, 0, 2, -4, 4, -1, 1, -5, 0, 4, 1, -1, -1, 2, -4, 2, 0, 0, 2, -2, 1, 1, -4, -2, 5, 1, -1, -5, 4, -2, 4, -1, -1, -1, 1, 0, 1, -1, -1, 2, -2, -1, 4, -4, 4, -2, 1, -1, -1, 2, 1, -1, -4, 2, 2, -2, 2, -1, -3, 5, -8, 6, -2, 2, 0, 2, -2 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,8

REFERENCES

Eric Weisstein, CRC Concise Encyclopedia of Mathematics, 1998, page 1321.

LINKS

Table of n, a(n) for n=3..105.

FORMULA

a(n) = -(1/2)*(A001223(n+1)-A001223(n))

a(n) = A036263(n)/2. - T. D. Noe, Oct 06 2006

EXAMPLE

a(6)=-1 because 13-(17+11)/2=-1.

MAPLE

a:=n->ithprime(n)-(ithprime(n+1)+ithprime(n-1))/2: seq(a(n), n=3..95); # Emeric Deutsch, Mar 02 2005

MATHEMATICA

f[n_] := Prime[n] - (Prime[n - 1] + Prime[n + 1])/2; Table[f[n], {n, 3, 107}] (* Robert G. Wilson v, Sep 25 2006 *)

#[[2]]-(#[[1]]+#[[3]])/2&/@Partition[Prime[Range[2, 110]], 3, 1] (* Harvey P. Dale, Sep 21 2013 *)

PROG

(PARI) a(n) = prime(n)-(prime(n+1)+prime(n-1))/2;

vector(100, n, a(n+2)) \\ Joerg Arndt, Jan 20 2015

CROSSREFS

Cf. A000040, A066875, A006562, A051634, A051635.

Sequence in context: A054534 A085769 A237422 * A131341 A124034 A211312

Adjacent sequences:  A102549 A102550 A102551 * A102553 A102554 A102555

KEYWORD

sign

AUTHOR

Yasutoshi Kohmoto, Feb 25 2005

EXTENSIONS

More terms from Emeric Deutsch, Mar 02 2005

STATUS

approved

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Last modified February 21 06:40 EST 2019. Contains 320371 sequences. (Running on oeis4.)