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A088924 Number of "9ish numbers" with n digits. 1
1, 18, 252, 3168, 37512, 427608, 4748472, 51736248, 555626232, 5900636088, 62105724792, 648951523128, 6740563708152, 69665073373368, 716985660360312, 7352870943242808, 75175838489185272, 766582546402667448 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

First difference of A016189. ("9" can be replaced by any other nonzero digit, however only the 9ish numbers are closed under dismal multiplication).

LINKS

D. Applegate, C program for dismal arithmetic and number theory

D. Applegate, M. LeBrun and N. J. A. Sloane, Dismal Arithmetic

Index entries for sequences related to dismal arithmetic

FORMULA

9*10^(n-1) - 8*9^(n-1)

EXAMPLE

a(2) = 18 because 19 29 39 49 59 69 79 89 90 91 92 93 94 95 96 97 98 99 are the eighteen two-digit 9ish numbers.

CROSSREFS

Cf. A016189 A011539.

Sequence in context: A060788 A144708 A020528 * A125475 A016175 A062141

Adjacent sequences:  A088921 A088922 A088923 * A088925 A088926 A088927

KEYWORD

base,easy,nonn

AUTHOR

Marc LeBrun (mlb(AT)well.com), Oct 23 2003

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Last modified February 16 01:56 EST 2012. Contains 205860 sequences.