a(n) = Sum_{k=1..n} phi(k)*phi(k+1)*phi(k+2), where phi(k) = A000010(k) is Euler's totient function.
A335131
a(n) = Sum_{k=1..n} phi(k)*phi(k+1)*phi(k+2), where phi(k) = A000010(k) is Euler's totient function.
Terms
- a(0) =2a(1) =6a(2) =22a(3) =38a(4) =86a(5) =134a(6) =278a(7) =374a(8) =614a(9) =774a(10) =1254a(11) =1542a(12) =2118a(13) =2502a(14) =3526a(15) =4294a(16) =6022a(17) =6886a(18) =8614a(19) =9574a(20) =12214a(21) =13974a(22) =17494a(23) =19414a(24) =23734a(25) =26326a(26) =32374a(27) =35062a(28) =41782a(29) =45622
External references
- oeis: A335131