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A229236
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Palindromic triangular number with palindromic index.
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2
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1, 3, 6, 66, 3003, 66066, 617716, 3544453, 6172882716, 30416261403, 61728399382716, 66056806460865066, 3549632679762369453, 354963215686512369453, 30416741529792514761403, 35496321045754012369453, 3041674104186814014761403
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OFFSET
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1,2
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LINKS
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EXAMPLE
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a(5)=3003 because 3003 is 77th triangular number and 77 is palindrome.
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MATHEMATICA
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Select[Table[{n, (n(n+1))/2}, {n, 10^8}], AllTrue[#, PalindromeQ]&][[;; , 2]] (* Harvey P. Dale, Jun 04 2023 *)
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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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EXTENSIONS
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STATUS
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approved
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