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A075688 Pair sums are even interprimes. 1
4, 8, 22, 232, 596, 4016, 7277650, 1749701948 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

In the sequence all pair sums are even interprimes which are in A075689. Next term of the sequence (if any) a(7) > 2750000. Is this sequence infinite?

No more terms < 1.76*10^10. - David Wasserman, Apr 06 2005

LINKS

Table of n, a(n) for n=1..8.

FORMULA

a(1)=4; smallest a(n) > a(n-1): a(1)+a(n), ..., a(n-1)+a(n) all are even interprimes.

EXAMPLE

a(1) = 4; a(1) + a(2) = 4 + 8 = 12 = ( 11 + 13 ) / 2, even interprime; a(1) + a(3) = 4 + 22 = 26 = ( 23 + 29 )/2, even interprime; a(2) + a(3) = 8 + 22 = 30 = ( 29 + 31 )/2, even interprime, etc.

CROSSREFS

Cf. A075689.

Sequence in context: A129788 A170938 A003684 * A026596 A181688 A243557

Adjacent sequences:  A075685 A075686 A075687 * A075689 A075690 A075691

KEYWORD

nonn

AUTHOR

Zak Seidov, Sep 25 2002

EXTENSIONS

More terms from David Wasserman, Apr 06 2005

STATUS

approved

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Last modified December 22 00:23 EST 2014. Contains 252326 sequences.