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A235049 Subtract one from each nonzero digit in decimal representation of n. 3
0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 10, 10, 11, 12, 13, 14, 15, 16, 17, 18, 20, 20, 21, 22, 23, 24, 25, 26, 27, 28, 30, 30, 31, 32, 33, 34, 35, 36, 37, 38, 40, 40, 41, 42, 43, 44, 45, 46, 47, 48, 50, 50, 51, 52, 53, 54, 55, 56, 57, 58, 60 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

Contains exactly the same terms as A007095, except that each occurs an infinite number of times.

A102683(a(n)) = 0. - Reinhard Zumkeller, Apr 16 2014

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..10000

Index entries for sequences related to decimal expansion of n

FORMULA

a(0) = 0, and for n>=1, if n = 0 modulo 10, a(n) = 10*a(n/10), otherwise a(n) = 10*a(floor(n/10)) + (n modulo 10) - 1.

EXAMPLE

Subtracting one from each nonzero digit of '9', we get 8, thus a(9)=8. Doing same for '10' results '00' thus a(10)=0. For '12', this results '01', thus a(12)=1.

PROG

(MIT/GNU Scheme, two implementations)

(define (A235049 n) (let loop ((z 0) (i 0) (n n)) (if (zero? n) z (let ((d (modulo n 10))) (loop (+ z (* (expt 10 i) (if (zero? d) d (- d 1)))) (1+ i) (floor->exact (/ n 10)))))))

;; As a recurrence, using memoization macro definec from Antti Karttunen's IntSeq-library:

(definec (A235049 n) (if (zero? n) n (let ((d (modulo n 10))) (+ (* 10 (A235049 (floor->exact (/ n 10)))) (if (zero? d) d (- d 1))))))

(Haskell)

a235049 x = if x == 0 then 0 else 10 * a235049 x' + max 0 (d - 1)

            where (x', d) = divMod x 10

-- Reinhard Zumkeller, Apr 16 2014

CROSSREFS

Cf. A007095.

Sequence in context: A037851 A037887 A207505 * A031087 A010878 A309788

Adjacent sequences:  A235046 A235047 A235048 * A235050 A235051 A235052

KEYWORD

nonn,easy,base,look

AUTHOR

Antti Karttunen, Apr 14 2014

STATUS

approved

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Last modified April 8 11:18 EDT 2020. Contains 333313 sequences. (Running on oeis4.)