

A065433


Numbers n such that there exist x, y with n^2 = x! + y!.


2




OFFSET

1,1


COMMENTS

Next term > 10^78.  Sascha Kurz, Mar 24 2002
a(6) > 10^1545.  Robert G. Wilson v, Apr 06 2006


LINKS

Table of n, a(n) for n=1..5.
Lev Emelyanov, Square as sum of two factorials


EXAMPLE

2^2 = 2!+2!; 5^2 = 4!+1!; 11^2 = 5!+1!; 12^2 = 5!+4!; 71^2 = 7!+1!.


MATHEMATICA

Sqrt@ Select[ Sort@ Flatten@ Table[x! + y!, {x, 650}, {y, x}], IntegerQ@ Sqrt@ # &] (* Robert G. Wilson v, Apr 06 2006 *)


CROSSREFS

Sequence in context: A231336 A283473 A062889 * A032541 A281644 A075749
Adjacent sequences: A065430 A065431 A065432 * A065434 A065435 A065436


KEYWORD

nonn


AUTHOR

Antreas P. Hatzipolakis (xpolakis(AT)otenet.gr), Nov 23 2001


STATUS

approved



