A088123 Let f(n,x) = 1 + 2x + 3x^2 + 5x^3 + 7x^4 + ... + prime(n)*x^n; a(n) = smallest value of x such that f(n,x) is a prime, or 0 if no such prime exists.

1, 2, 1, 6, 1, 6, 1, 8, 1, 74, 6, 6, 1, 2, 11, 102, 20, 88, 1, 52, 10, 18, 2, 56, 1, 26, 37, 216, 1, 78, 1, 28, 21, 160, 3, 276, 30, 1542, 42, 598, 20, 20, 333, 186, 8, 82, 11, 90, 1, 246, 1, 240, 83, 58, 9, 76, 1, 16, 21, 700, 60, 10, 87, 250, 62, 406, 2, 502, 140, 186, 1293, 578

Offset: 1

Author

Amarnath Murthy, Sep 25 2003

Keywords

• nonn

Examples

			a(4) = 6 as, A088122(4) = 10273 = f(4,6).
		

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..200

Crossrefs

Cf. A088122.

Programs

Mathematica

Table[Clear[x,n,eq];eq=Total[Table[Prime[n]x^n,{n,t}]]+1;x=1; While[ !PrimeQ[ eq],x++];x,{t,80}] (* Harvey P. Dale, Apr 27 2013 *)

Extensions

More terms from Tom Mueller, May 04 2004

More terms from David Wasserman, Jul 25 2005