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

0,3

Links

Table of n, a(n) for n=0..35.

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.

Prog

(Scheme, two variants)
(definec (A261233 n) (if (zero? n) n (+ (A261234 (- n 1)) (A261233 (- n 1)))))
(define (A261233 n) (A261231 (- (A000244 n) 1)))

Crossrefs

One less than A261232.

Cf. A000244, A261231.

Cf. A261234 (the first differences).

Cf. also A218600.

Sequence in context: A171853 A330458 A093963 * A346944 A027219 A085831

Adjacent sequences: A261230 A261231 A261232 * A261234 A261235 A261236

Keyword

nonn

Author

Antti Karttunen, Aug 13 2015

Extensions

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

Status

approved