Additive persistence: number of summations of digits needed to obtain a single digit (the additive digital root).

A031286

Additive persistence: number of summations of digits needed to obtain a single digit (the additive digital root).

Terms

    a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =0a(8) =0a(9) =0a(10) =1a(11) =1a(12) =1a(13) =1a(14) =1a(15) =1a(16) =1a(17) =1a(18) =1a(19) =2a(20) =1a(21) =1a(22) =1a(23) =1a(24) =1a(25) =1a(26) =1a(27) =1a(28) =2a(29) =2

External references