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A065983
Palindromes whose digit sum is 4.
0
4, 22, 121, 202, 1111, 2002, 10201, 11011, 20002, 101101, 110011, 200002, 1002001, 1010101, 1100011, 2000002, 10011001, 10100101, 11000011, 20000002, 100020001, 100101001, 101000101, 110000011, 200000002, 1000110001, 1001001001
OFFSET
1,1
COMMENTS
There are ceiling(k/2) terms with k digits and so floor(n^2/4) terms with fewer than k digits. Writing the terms as a vertical column and then blanking zeros produces a narrow triangle with upward chevrons.
CROSSREFS
Cf. A062397 and A066138 for digit sums of 2 and 3.
Sequence in context: A261193 A025569 A098834 * A236576 A375724 A185858
KEYWORD
base,nonn
AUTHOR
Henry Bottomley, Dec 10 2001
STATUS
approved