

A186886


Least number k having exactly n prime divisors and the Stern polynomial B(k,x) is irreducible.


1




OFFSET

1,1


COMMENTS

Ulas and Ulas tabulate these values and conjecture 6.5, p.20, that a(n) exists for all n.
See A125184 for the Stern polynomials. See A186891 for n such that the Stern polynomial B_n(x) is irreducible.


LINKS

Table of n, a(n) for n=1..7.
Maciej Ulas and Oliwia Ulas, On certain arithmetic properties of Stern polynomials, arXiv:1102.5109 [math.CO], 2011.


EXAMPLE

a(1) = 2.
a(2) = 55 = 5 * 11.
a(3) = 665 = 5 * 7 * 19.
a(4) = 6545 = 5 * 7 * 11 * 17.
a(5) = 85085 = 5 * 7 * 11 * 13 * 17.
a(6) = 1616615 = 5 * 7 * 11 * 13 * 17 * 19.
a(7) = 37182145 = 5 * 7 * 11 * 13 * 17 * 19 * 23.


CROSSREFS

Cf. A125184, A186891.
Sequence in context: A157262 A007975 A109796 * A024029 A134501 A210928
Adjacent sequences: A186883 A186884 A186885 * A186887 A186888 A186889


KEYWORD

nonn,more


AUTHOR

Jonathan Vos Post, Feb 28 2011


STATUS

approved



