Numbers k such that phi(k) + phi(k+1) divides sigma(k) + sigma(k+1).

Terms

a(0) =1a(1) =5a(2) =52a(3) =55a(4) =185a(5) =506a(6) =551a(7) =590a(8) =644a(9) =667a(10) =707a(11) =2285a(12) =2587a(13) =2758a(14) =7551a(15) =10366a(16) =11336a(17) =11564a(18) =11798a(19) =12750a(20) =16616a(21) =16703a(22) =16764a(23) =17383a(24) =18239a(25) =24350a(26) =24415a(27) =26586a(28) =33263a(29) =35541