A088125 Let f(n,x) = 1 + 4*x + 6*x^2 + 8*x^3 + 9*x^4 + ... + composite(n)*x^n; a(n) = smallest x such that f(n,x) is a prime, or 0 if no such prime exists.
1, 1, 1, 2, 6, 34, 2, 1, 3, 1, 11, 42, 120, 12, 8, 1, 4, 2, 24, 86, 1, 54, 154, 202, 246, 25, 10, 60, 1, 114, 34, 22, 21, 1, 88, 14, 276, 70, 795, 518, 448, 252, 6, 2, 1, 18, 768, 124, 1, 186, 143, 1, 138, 456, 366, 19, 47, 112, 336, 772, 140, 3, 88, 30, 188, 90, 437, 90, 294
Offset: 1
Keywords
Links
- Robert Israel, Table of n, a(n) for n = 1..400
- Wikipedia, Bunyakovsky conjecture
Programs
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Maple
P:= 1: q:= 1: for n from 1 to 100 do q:= q+1; while isprime(q) do q:= q+1 od; P:= P + q*x^n; if not irreduc(P) then A[n]:= 0 else Pf:= unapply(P,x); for xx from 1 while not isprime(Pf(xx)) do od: A[n]:= xx; fi od: seq(A[n],n=1..100); # Robert Israel, Jul 01 2018
Extensions
More terms from Tom Mueller (muel4503(AT)uni-trier.de), May 04 2004
More terms from David Wasserman, Jul 25 2005
Comments