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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. 4
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

EXAMPLE

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

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 *)

CROSSREFS

Cf. A088122.

Sequence in context: A205959 A318503 A328580 * A050932 A286515 A166120

Adjacent sequences:  A088120 A088121 A088122 * A088124 A088125 A088126

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Sep 25 2003

EXTENSIONS

More terms from Tom Mueller, May 04 2004

More terms from David Wasserman, Jul 25 2005

STATUS

approved

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Last modified December 15 04:23 EST 2019. Contains 329991 sequences. (Running on oeis4.)