Fermat pseudoprimes to base 2 that are triangular.

Terms

a(0) =561a(1) =2701a(2) =4371a(3) =8911a(4) =10585a(5) =18721a(6) =33153a(7) =41041a(8) =49141a(9) =93961a(10) =104653a(11) =115921a(12) =157641a(13) =226801a(14) =289941a(15) =314821a(16) =334153a(17) =534061a(18) =665281a(19) =721801a(20) =831405a(21) =873181a(22) =915981a(23) =1004653a(24) =1373653a(25) =1537381a(26) =1755001a(27) =1815465a(28) =1987021a(29) =2035153