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A130308 Primes of the form [n!! - (n-1)!! + (n-2)!! -....1!! ]-1. 1
5, 317, 1217216458429656137 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

The next term is too large to include.

EXAMPLE

5 = 4!! - 3!! + 2!! - 1!! -1 = 8 - 3 + 2 - 1 - 1.

MAPLE

P:=proc(n) local a, i, j, k, w; for i from 1 by 1 to n do a:=0; for j from i by -1 to 0 do k:=j; w:=j-2; while w>0 do k:=k*w; w:=w-2; od; a:=a+k*(-1)^j od; if isprime(abs(a)-1) then print(abs(a)-1); fi; od; end: P(1000);

CROSSREFS

Cf. A071828, A130309.

Sequence in context: A075983 A160071 A094161 * A053516 A085523 A152425

Adjacent sequences:  A130305 A130306 A130307 * A130309 A130310 A130311

KEYWORD

nonn,bref

AUTHOR

Paolo P. Lava & Giorgio Balzarotti (paoloplava(AT)gmail.com), May 21 2007

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Last modified February 17 00:09 EST 2012. Contains 205978 sequences.