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A319477
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Nonnegative integers which cannot be obtained by adding exactly two nonzero decimal palindromes.
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5
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0, 1, 21, 32, 43, 54, 65, 76, 87, 98, 111, 131, 141, 151, 161, 171, 181, 191, 201, 1031, 1041, 1042, 1051, 1052, 1053, 1061, 1062, 1063, 1064, 1071, 1072, 1073, 1074, 1075, 1081, 1082, 1083, 1084, 1085, 1086, 1091, 1092, 1093, 1094, 1095, 1096, 1097, 1099
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OFFSET
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1,3
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COMMENTS
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Every integer larger than two can be obtained by adding exactly three nonzero decimal palindromes.
The nonzero palindromes of this sequence are in A213879.
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LINKS
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FORMULA
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MAPLE
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p:= proc(n) option remember; local i, s; s:= ""||n;
for i to iquo(length(s), 2) do if
s[i]<>s[-i] then return false fi od; true
end:
h:= proc(n) option remember; `if`(n<1, 0,
`if`(p(n), n, h(n-1)))
end:
b:= proc(n, i, t) option remember; `if`(n=0, 1, `if`(t*i<n,
0, b(n, h(i-1), t)+b(n-i, h(min(n-i, i)), t-1)))
end:
g:= n-> (k-> b(n, h(n), k)-b(n, h(n), k-1))(2):
a:= proc(n) option remember; local j; for j from 1+
`if`(n=1, -1, a(n-1)) while g(j)<>0 do od; j
end:
seq(a(n), n=1..80);
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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