Numbers k that divide Sum_{j=1..k} A051953(j) where A051953(j) = j - Phi(j). Arithmetic mean of first k cototient values is an integer.

A063986

Numbers k that divide Sum_{j=1..k} A051953(j) where A051953(j) = j - Phi(j). Arithmetic mean of first k cototient values is an integer.

Terms

    a(0) =1a(1) =4a(2) =5a(3) =24a(4) =25a(5) =249a(6) =600a(7) =617a(8) =12272a(9) =13763a(10) =21332a(11) =25228a(12) =783665a(13) =15748051a(14) =41846733a(15) =195853251a(16) =2488541984a(17) =14399065016a(18) =21119309213a(19) =22430204140a(20) =43787603128a(21) =157825075944a(22) =206651865067a(23) =271605149320a(24) =374049315076a(25) =650288309748

External references