A105302 - OEIS

%I #6 May 06 2022 11:24:00

%S 665545362821,496465435406378351,946903861820780741,

%T 112810811035990946903,195318911830177017111653,

%U 382837413655357034863403,133661320313041128801272012561

%N Primes formed by reverse concatenation of 6 consecutive triangular numbers.

%H Harvey P. Dale, <a href="/A105302/b105302.txt">Table of n, a(n) for n = 1..2500</a>

%e a(1)=665545362821 because 665545362821 is the prime formed by reverse concatenation of 6 consecutive triangular numbers i.e. 21,28,36,45,55 and 66.

%t Select[FromDigits[Flatten[IntegerDigits/@Reverse[#]]]&/@Partition[Accumulate[ Range[ 200]],6,1],PrimeQ] (* _Harvey P. Dale_, May 06 2022 *)

%K base,nonn

%O 1,1

%A _Shyam Sunder Gupta_, Apr 25 2005