A261233 a(n) = number of steps to reach 0 when starting from k = (3^n)-1 and repeatedly applying the map that replaces k with k - (sum of digits in base-3 representation of k).

0, 1, 3, 8, 20, 49, 123, 319, 849, 2294, 6250, 17112, 47013, 129605, 358838, 998805, 2796093, 7869800, 22251147, 63141639, 179701239, 512744599, 1466635089, 4205423895, 12087339723, 34816804310, 100469592521, 290336059740, 839932833290, 2432050970420, 7047731703137, 20440131344750, 59334695322383, 172409162871823, 501489513690423, 1460214792034791

Offset: 0

Author

Antti Karttunen, Aug 13 2015

Keywords

• nonn

Crossrefs

One less than A261232.

Cf. A000244, A261231.

Cf. A261234 (the first differences).

Cf. also A218600.

Formula

a(0) = 0; for n >= 1, a(n) = A261234(n-1) + a(n-1).

a(n) = A261231((3^n)-1).

a(n) = A261232(n)-1.

Extensions

Terms from a(24) onward added from the output of Hiroaki Yamanouchi's program by Antti Karttunen, Aug 16 2015