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A056141 primefloor[n]*primeceiling[n]-previousprime[n]*nextprime[n]. 2
-1, 0, 4, 0, -6, 0, 0, 0, 30, 0, -18, 0, 0, 0, 42, 0, -30, 0, 0, 0, -22, 0, 0, 0, 0, 0, 128, 0, -112, 0, 0, 0, 0, 0, 98, 0, 0, 0, 90, 0, -78 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,3

LINKS

Table of n, a(n) for n=3..43.

FORMULA

a(n)=A007917(n)*A007918(n)-A007917(n-1)*A007918(n+1) =A030664(n)-A013638(n) =A056140(n)-A056139(n)

EXAMPLE

a(n)=A056140(n) if n is prime, a(n)=0 otherwise

a(3)=3*3-2*5=-1, a(4)=3*5-3*5=0

CROSSREFS

Cf. A056139, A056140.

Sequence in context: A308678 A184365 A126813 * A246004 A103688 A125961

Adjacent sequences:  A056138 A056139 A056140 * A056142 A056143 A056144

KEYWORD

easy,sign

AUTHOR

Henry Bottomley, Jun 15 2000

STATUS

approved

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Last modified October 15 07:56 EDT 2019. Contains 328026 sequences. (Running on oeis4.)