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%I #10 Mar 27 2024 17:00:19
%S 5,35,70,92,145,376,1520,1820,3577,3725,7526,9322,9560,10045,10292,
%T 13490,14065,16801,17767,18760,32782,34126,34580,36895,38320,38801,
%U 39772,73151,74482,76501,78547,91390,93625,94376,98176,100492,101270
%N Pentagonal numbers (A000326) whose digit reversal is a prime.
%H Harvey P. Dale, <a href="/A115707/b115707.txt">Table of n, a(n) for n = 1..1000</a>
%e 145 is the 10th pentagonal number and 541 is prime.
%t Select[Table[n (3n-1)/2,{n,400}],PrimeQ[FromDigits[Reverse[ IntegerDigits[ #]]]]&] (* _Harvey P. Dale_, Feb 23 2011 *)
%t Select[PolygonalNumber[5,Range[300]],PrimeQ[IntegerReverse[#]]&] (* _Harvey P. Dale_, Mar 27 2024 *)
%Y Cf. A000326, A115706.
%K nonn,base
%O 1,1
%A _Giovanni Resta_, Jan 31 2006
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