New World Record Near-repdigit Palindrome Prime

The base ten near-repdigit palindrome 10^290253-2*10^145126-1 is a prime number. It's the largest known palindromic prime, and only the second known prime of the form 10^(2*x+1)-2*10^x-1 (correction: for x>0).

Written out, it's 145126 nines, a seven, and 145126 more nines.

Leap Day Near-repdigit Palindrome Prime!

10^269479-7*10^134739-1 is prime! This is a new world record for near-repdigit palindrome primes. It is also the second largest known palindromic prime and one of the top twenty largest near-repdigit primes (as of the date of discovery, February 29, 2012).