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 sigma(n) - n = Sum_{i=1..k-1}{sigma(Sum_{j=1..i}{d_(j)*10^(j-1)}) - Sum_{j=1..i}{d_(j)*10^(j-1)}} (see example below).
A240894
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 sigma(n) - n = Sum_{i=1..k-1}{sigma(Sum_{j=1..i}{d_(j)*10^(j-1)}) - Sum_{j=1..i}{d_(j)*10^(j-1)}} (see example below).
Terms
- a(0) =13a(1) =17a(2) =23a(3) =37a(4) =43a(5) =47a(6) =53a(7) =67a(8) =73a(9) =83a(10) =97a(11) =131a(12) =211a(13) =241a(14) =271a(15) =311a(16) =331a(17) =431a(18) =461a(19) =541a(20) =571a(21) =631a(22) =641a(23) =661a(24) =761a(25) =811a(26) =899a(27) =911a(28) =941a(29) =971
External references
- oeis: A240894