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A099767 Number of n-digit palindromes in base n. 0
1, 6, 12, 100, 180, 2058, 3584, 52488, 90000, 1610510, 2737152, 57921708, 97883968, 2392031250, 4026531840, 111612119056, 187339329792, 5808378560022, 9728000000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

LINKS

Table of n, a(n) for n=2..20.

FORMULA

a(n) = (n - 1)*n^([(n + 1)/2] - 1) where [] is the greatest integer function

EXAMPLE

a(3) = 6 because there are 6 3-digit palindromes in base 3, namely 101, 111, 121, 202, 212, 222.

MATHEMATICA

(n - 1)*n^(Floor[(n + 1)/2] - 1) /. n -> Range[2, 20]

CROSSREFS

Sequence in context: A181597 A002898 A003613 * A191462 A080450 A144760

Adjacent sequences:  A099764 A099765 A099766 * A099768 A099769 A099770

KEYWORD

easy,nonn,base

AUTHOR

Anonymous, Nov 11 2004

STATUS

approved

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Last modified August 20 22:45 EDT 2019. Contains 326155 sequences. (Running on oeis4.)