A162490 Least prime of the form x^y+y^x with x = A162488(n) > y > 1.

17, 593, 32993, 2097593, 59604644783353249, 43143988327398957279342419750374600193, 8589935681, 5052785737795758503064406447721934417290878968063369478337

Offset: 1

Author

M. F. Hasler, Jul 04 2009

Keywords

• nonn

Comments

Sequences A162488 and A162489 list the corresponding x and y values.

Sequence A094133 lists these primes ordered by their size (without multiplicity). See there for more information, links and references.

Examples

			The least x such that x^y+y^x is prime for some x>y>1 is A162488(1)=3, for y=A162489(1)=2, yielding the prime a(1) = 9 + 8 = 17.
		

Crossrefs

Cf. A094133, A162486 - A162489.

Programs

PARI

for(i=3,999,for(j=2,i-1,isprime(i^j+j^i)||next;print1(i^j+j^i", ");break))

Formula

a(n) = A162488(n)^A162489(n) + A162489(n)^A162488(n).