Numbers k such that sigma(k) = phi(k+1) + phi(k) + phi(k-1).

Terms

a(0) =6a(1) =147a(2) =286a(3) =376a(4) =534a(5) =738a(6) =805a(7) =2392a(8) =2406a(9) =4324a(10) =8214a(11) =9606a(12) =10362a(13) =12126a(14) =16263a(15) =17511a(16) =27639a(17) =29151a(18) =39215a(19) =48616a(20) =60687a(21) =61132a(22) =61915a(23) =141526a(24) =142610a(25) =147890a(26) =153530a(27) =160748a(28) =189501a(29) =212134