A217657 Delete the initial digit in decimal representation of n.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20

Offset

0,13

Comments

When n - a(n)*10^[log_10 n] >= 10^[(log_10 n) - 1], where [] denotes floor, or when n < 100 and 10|n, n is the concatenation of A000030(n) and a(n) - corrected by Glen Whitney, Jul 01 2022

a(110) = 10 is the first term > 9. The sequence consists of 10 repetitions of 0 (n = 0..9), then 9 repetitions of {0, ..., 9} (n = 10..99), then 9 repetitions of {0, ..., 99} (n = 100..999), and so on. - M. F. Hasler, Oct 18 2017

Links

Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

Formula

a(n) = 0 if n <= 9, otherwise 10*a(floor(n/10)) + n mod 10.

a(n) = n mod 10^floor(log_10(n)), a(0) = 0. - M. F. Hasler, Oct 18 2017

Mathematica

Array[FromDigits@ Rest@ IntegerDigits@ # &, 121, 0] (* Michael De Vlieger, Dec 22 2019 *)

Prog

(Haskell)
a217657 n | n <= 9    = 0
          | otherwise = 10 * a217657 n' + m where (n', m) = divMod n 10
(PARI) apply( A217657(n)=n%10^logint(n+!n, 10), [0..199]) \\ M. F. Hasler, Oct 18 2017, edited Dec 22 2019
(Python)
def a(n): return 0 if n < 10 else int(str(n)[1:])
print([a(n) for n in range(121)]) # Michael S. Branicky, Jul 01 2022

Crossrefs

Cf. A059995 (drop final digit of n), A000030 (initial digit of n), A202262.

Sequence in context: A118943 A010879 A179636 * A175419 A175422 A175423

Adjacent sequences: A217654 A217655 A217656 * A217658 A217659 A217660

Keyword

nonn,base,look

Author

Reinhard Zumkeller, Oct 10 2012

Extensions

Data extended to include the first terms larger than 9, by M. F. Hasler, Dec 22 2019

Status

approved