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

Author

N. J. A. Sloane, Mar 11 2012

Keywords

• nonn
• base
• easy

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]

Examples

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

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).

Crossrefs

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

Programs

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