A209685 Sum of last two digits of n.

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

Offset

0,3

Comments

Note that "Sum of last three digits of n" takes the same values as this sequence for n <= 99 (but not for n = 100). "Sum of last three digits of n" repeats every 1000 terms, while this sequence repeats every 100 values. Analogs are obvious for "sum of the last 4 values of n" which repeats every 10^4 values. - Jonathan Vos Post, Mar 12 2012 [First sentence corrected by N. J. A. Sloane, Feb 12 2017]

Links

Indranil Ghosh, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1).

Example

99->9+9=18, 100->0+0=0.

Prog

(PARI) a(n)=n%100\10+n%10 \\ Charles R Greathouse IV, Mar 11 2012
(Python)
def A209685(n):
....if n<=9:return n
....return int(str(n)[-1])+int(str(n)[-2]) # Indranil Ghosh, Feb 12 2017

Crossrefs

Cf. A209674, A080463. Differs from A007953 and A076314 at n=100.

Sequence in context: A076314 A007953 A080463 * A114570 A349194 A342829

Adjacent sequences: A209682 A209683 A209684 * A209686 A209687 A209688

Keyword

nonn,base,easy

Author

N. J. A. Sloane, Mar 11 2012

Status

approved