a(n) is the smallest integer m such that m-n is composite and phi(m+n) + sigma(m-n) = 2*m.

Terms

a(0) =11a(1) =8a(2) =13a(3) =37350a(4) =25a(5) =18a(6) =28a(7) =20a(8) =61a(9) =22a(10) =44a(11) =40a(12) =52a(13) =250a(14) =39a(15) =60a(16) =68a(17) =60a(18) =58a(19) =76a(20) =168a(21) =46a(22) =92a(23) =69a(24) =2040a(25) =56a(26) =126a(27) =84a(28) =114a(29) =140