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%I #6 Jul 27 2019 15:38:38
%S 7140702169036786667065556441,16110159311575315576154001522515051,
%T 47586472784697146665463604605645753,
%U 55278549465461554285539565362853301
%N Primes formed by reverse concatenation of 7 consecutive triangular numbers.
%H Harvey P. Dale, <a href="/A105301/b105301.txt">Table of n, a(n) for n = 1..1000</a>
%e 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.
%t Select[FromDigits[Flatten[IntegerDigits/@#]]&/@(Reverse/@Partition[ Accumulate[ Range[500]],7,1]),PrimeQ] (* _Harvey P. Dale_, Jul 27 2019 *)
%K base,nonn
%O 1,1
%A _Shyam Sunder Gupta_, Apr 25 2005