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A093472
(2n+1)-digit anti-palindromic numbers or numberdromes, whose first and last digits add to ten, second and next-to-last add to ten and so on with the central digit a 5.
1
159, 258, 357, 456, 555, 654, 753, 852, 951, 11599, 12589, 13579, 14569, 15559, 16549, 17539, 18529, 19519, 21598, 22588, 23578, 24568, 25558, 26548, 27538, 28528, 29518, 31597, 32587, 33577, 34567, 35557, 36547, 37537, 38527, 39517
OFFSET
0,1
FORMULA
a(n) = (10^(m+1))n+5(10^m)+(10^m-n)
EXAMPLE
a(1) = 159 because at least three digits are required, so that n = 1, m = 1 yields a(1) = 100+50+(10-1) = 159
CROSSREFS
Cf. A083678.
Sequence in context: A045260 A280967 A192173 * A270304 A281665 A329535
KEYWORD
easy,nonn,base
AUTHOR
Michael Joseph Halm, May 13 2004
STATUS
approved