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A109625
Numbers n such that concatenation of n and its 10's complement is a palindrome.
0
5, 91, 9091, 9181, 9271, 9361, 9451, 9541, 9631, 9721, 9811, 900991, 901891, 902791, 903691, 904591, 905491, 906391, 907291, 908191, 909091, 910981, 911881, 912781, 913681, 914581, 915481, 916381, 917281, 918181, 919081, 920971, 921871, 922771
OFFSET
1,1
EXAMPLE
a(3)=9091 because 10^4-9091 = 909 and concatenating produces the palindrome
9091909.
MATHEMATICA
Select[Range[923000], PalindromeQ[FromDigits[Join[IntegerDigits[#], IntegerDigits[ 10^IntegerLength[ #]-#]]]]&] (* Harvey P. Dale, Nov 01 2022 *)
CROSSREFS
Sequence in context: A368776 A340052 A340883 * A266290 A348347 A222903
KEYWORD
base,nonn
AUTHOR
Jason Earls, Aug 02 2005
STATUS
approved