Williams primes of the form 4•5ⁿ+1

2016-01-16: Checked to n = 300000 , <a href="/z/index.php?title=Robert_Price&amp;action=edit&amp;redlink=1" class="new" title="Robert Price (page does not exist)">Robert Price
2004-05-10: Found n =&#160;70130 , Peter Benson
2000-07-18: Found n =&#160;20462 , <a href="/z/index.php?title=Roberto_E._Martinez&amp;action=edit&amp;redlink=1" class="new" title="Roberto E. Martinez (page does not exist)">Roberto E. Martinez

Current data

2, 6, 18, 50, 290, 2582, 20462^[1], 23870, 26342, 31938, 38122, 65034, 70130^[2], 245538

Remarks :

The sequence A204322 in OEIS