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A066580 Let N = 123456789123456789123456789..., with the digits from 1 to 9 repeated indefinitely. Then a(n) is the n-digit number formed from the digits starting at the {(n(n-1)/2 +1}-th position of N, read backwards if n is even. 0
1, 32, 456, 1987, 23456, 321987, 4567891, 98765432, 123456789, 1987654321, 23456789123, 654321987654, 7891234567891, 65432198765432, 789123456789123, 1987654321987654, 23456789123456789, 987654321987654321 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..18.

EXAMPLE

a(3) = 456, the 3-digit number formed from the 4th digit onwards of N.

a(6) = 321987, the reversed 6-digit number formed from the 16th digit of N.

CROSSREFS

Sequence in context: A274802 A274748 A283811 * A076070 A133348 A010837

Adjacent sequences:  A066577 A066578 A066579 * A066581 A066582 A066583

KEYWORD

base,easy,nonn

AUTHOR

Amarnath Murthy, Dec 20 2001

EXTENSIONS

More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 01 2003

STATUS

approved

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Last modified December 4 13:29 EST 2021. Contains 349526 sequences. (Running on oeis4.)