Position of n-th 5 in A031087.

Terms

a(0) =5a(1) =19a(2) =37a(3) =55a(4) =73a(5) =82a(6) =84a(7) =86a(8) =88a(9) =90a(10) =91a(11) =92a(12) =94a(13) =96a(14) =98a(15) =109a(16) =127a(17) =145a(18) =168a(19) =195a(20) =222a(21) =249a(22) =276a(23) =289a(24) =292a(25) =295a(26) =298a(27) =301a(28) =303a(29) =304