Consider a number of k digits n = d_(k)*10^(k-1) + d_(k-1)*10^(k-2) + … + d_(2)*10 + d_(1). Sequence lists the numbers n such that Sum_{i=1..k-1}{sigma(Sum_{j=1..i}{d_(j)*10^(j-1)})} = Sum_{i=1..k-1}{phi(Sum_{j=1..i}{d_(k-j+1)*10^(i-j)})} (see example below).
A244068
Consider a number of k digits n = d_(k)*10^(k-1) + d_(k-1)*10^(k-2) + … + d_(2)*10 + d_(1). Sequence lists the numbers n such that Sum_{i=1..k-1}{sigma(Sum_{j=1..i}{d_(j)*10^(j-1)})} = Sum_{i=1..k-1}{phi(Sum_{j=1..i}{d_(k-j+1)*10^(i-j)})} (see example below).
Terms
- a(0) =11a(1) =12a(2) =35a(3) =38a(4) =57a(5) =59a(6) =152a(7) =599a(8) =2812a(9) =3419a(10) =3915a(11) =6733a(12) =11671a(13) =16706a(14) =16714a(15) =16858a(16) =25303a(17) =26752a(18) =128257a(19) =171762a(20) =238571a(21) =265872a(22) =345715a(23) =375923a(24) =486141a(25) =496975a(26) =573433a(27) =1492832a(28) =2324671a(29) =2944061
External references
- oeis: A244068