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A276115
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Numbers whose digits have a permutation that is a palindrome.
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1
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1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, 44, 55, 66, 77, 88, 99, 101, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 121, 122, 131, 133, 141, 144, 151, 155, 161, 166, 171, 177, 181, 188, 191, 199, 202, 211, 212, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 232, 233, 242, 244, 252, 255, 262, 266
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OFFSET
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1,2
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COMMENTS
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Permutations with leading zeros are not considered as palindromic, thus (for example) 10 is not included in the sequence.
Also numbers in which at most 1 digit occurs an odd number of times and (if there is more than one digit) at least 2 digits are nonzero. - David A. Corneth, Aug 21 2016, corrected by Robert Israel, Aug 31 2016
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LINKS
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MAPLE
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filter:= proc(n) local L, M;
if n < 10 then return true fi;
L:= convert(n, base, 10);
M:= [seq(numboccur(j, L), j=0..9)];
convert(M mod 2, `+`) <= 1 and convert(M[2..-1], `+`)>=2
end proc:
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PROG
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(PARI) is(n) = {my(v = concat(vecsort(digits(n)), ["a"]), prev=1, odd=0); if(#v>2&&v[#v-2]==0, return(0)); for(i=1, #v-1, if(v[i]!=v[i+1], odd+=(i-prev+1)%2; if(odd==2, return(0)); prev = i + 1)); 1} \\ David A. Corneth, Aug 21 2016
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CROSSREFS
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Cf. A084050 (for a sequence where leading zero numbers are included).
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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