Multiples of 13.

Terms

a(0) =0a(1) =13a(2) =26a(3) =39a(4) =52a(5) =65a(6) =78a(7) =91a(8) =104a(9) =117a(10) =130a(11) =143a(12) =156a(13) =169a(14) =182a(15) =195a(16) =208a(17) =221a(18) =234a(19) =247a(20) =260a(21) =273a(22) =286a(23) =299a(24) =312a(25) =325a(26) =338a(27) =351a(28) =364a(29) =377