a(n) is the smallest n-gonal number that is a Fermat pseudoprime to base 2 (A001567), or -1 if no such number exists.

A371759

a(n) is the smallest n-gonal number that is a Fermat pseudoprime to base 2 (A001567), or -1 if no such number exists.

Terms

    a(0) =561a(1) =1194649a(2) =7957a(3) =561a(4) =23377a(5) =341a(6) =129889a(7) =1105a(8) =35333a(9) =561a(10) =204001a(11) =31609a(12) =2940337a(13) =1105a(14) =493697a(15) =8481a(16) =13981a(17) =1905a(18) =88561a(19) =41665a(20) =10680265a(21) =1729a(22) =107185a(23) =264773a(24) =449065a(25) =6601a(26) =2165801a(27) =23001a(28) =1141141a(29) =13981

External references