Composite numbers k such that sigma(k)*phi(k) + 2*(k+1) is a square.

Terms

a(0) =1169a(1) =7777a(2) =41111a(3) =46097a(4) =668167a(5) =846817a(6) =2107519a(7) =3612769a(8) =17424241a(9) =30666527a(10) =37526993a(11) =56323393a(12) =214746055a(13) =383523857a(14) =512376769a(15) =1021934641a(16) =1228492849a(17) =1303949599a(18) =4056001351a(19) =7425397169a(20) =17073544447a(21) =17859428369a(22) =18452226887a(23) =46874737969a(24) =51411954391