Indices of 4th powers (of primes) in the 4-almost primes.

Terms

a(0) =1a(1) =8a(2) =90a(3) =385a(4) =2556a(5) =5138a(6) =15590a(7) =24646a(8) =53993a(9) =139199a(10) =182476a(11) =375363a(12) =569617a(13) =691012a(14) =991150a(15) =1613115a(16) =2490040a(17) =2849478a(18) =4163793a(19) =5263838a(20) =5888203a(21) =8100907a(22) =9886861a(23) =13102875a(24) =18538021a(25) =21816421a(26) =23608907a(27) =27525519a(28) =29659283a(29) =34290671