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A105301
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Primes formed by reverse concatenation of 7 consecutive triangular numbers.
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1
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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(1)=7140702169036786667065556441 because 7140702169036786667065556441 is the prime formed by reverse concatenation of 7 consecutive triangular numbers i.e. 6441,6555,6670,6786,6903,7021 and 7140.
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MATHEMATICA
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Select[FromDigits[Flatten[IntegerDigits/@#]]&/@(Reverse/@Partition[ Accumulate[ Range[500]], 7, 1]), PrimeQ] (* Harvey P. Dale, Jul 27 2019 *)
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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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STATUS
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approved
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