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A089316
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Prime worms [successive digit differences with absolute value of 2].
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2
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131, 313, 353, 757, 797, 35353, 35753, 75797, 79757, 97579, 3131353, 3135313, 3531313, 7535797, 313131353, 313135313, 313579753, 353535313, 357531313, 357531353, 357535753, 357575753, 357975353, 753535357, 757975357, 975353579
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OFFSET
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0,1
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LINKS
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FORMULA
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Select prime numbers having the same first and last digits; if the uniform absolute value of successive digit differences is 2, add to sequence.
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EXAMPLE
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a(4)=797; first and last digits are 7; abs(7-9)=2; abs(9-7)=2; the worm is 7.
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MATHEMATICA
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pwQ[n_]:=Module[{idn=IntegerDigits[n]}, First[idn]==Last[idn]&&Union[Abs[ Differences[idn]]]=={2}]; Select[Prime[Range[50000000]], pwQ] (* Harvey P. Dale, Mar 26 2013 *)
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CROSSREFS
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KEYWORD
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easy,nonn,base
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AUTHOR
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STATUS
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approved
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