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A072363
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Composite numbers whose sum of divisors is palindromic.
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2
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4, 81, 96, 98, 130, 146, 162, 166, 201, 205, 208, 221, 244, 274, 300, 314, 325, 333, 365, 388, 422, 438, 489, 519, 559, 633, 685, 793, 803, 1376, 1419, 1505, 1548, 1806, 1841, 2021, 2268, 2284, 2305, 2561, 2611, 2666, 2751, 2763, 2838, 2881, 2892, 2967, 3010
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OFFSET
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1,1
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LINKS
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EXAMPLE
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a(2) = 81: sum of divisors of 81 = 1+3+9+27+81 = 121, which is a palindrome.
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MATHEMATICA
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Select[Range[3000], CompositeQ[#] && PalindromeQ @ DivisorSigma[1, #] &] (* Amiram Eldar, Aug 17 2020 *)
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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