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A105294 Primes formed by concatenation of 3 consecutive triangular numbers. 1

%I #5 Nov 21 2013 12:48:40

%S 210231253,496528561,630666703,780820861,99010351081,495050505151,

%T 918093169453,9730987010011,120901224612403,135301369513861,

%U 201002030120503,223662257822791,368563712837401,379503822638503

%N Primes formed by concatenation of 3 consecutive triangular numbers.

%H Harvey P. Dale, <a href="/A105294/b105294.txt">Table of n, a(n) for n = 1..1000</a>

%e a(1)=210231253 because 210231253 is the prime formed by concatenation of 3 consecutive triangular numbers i.e. 210,231 and 253.

%t Select[FromDigits[Flatten[IntegerDigits[#]]]&/@Partition[Accumulate[ Range[300]], 3,1],PrimeQ] (* _Harvey P. Dale_, Sep 29 2011 *)

%K base,nonn

%O 1,1

%A _Shyam Sunder Gupta_, Apr 25 2005

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Last modified March 28 11:46 EDT 2024. Contains 371241 sequences. (Running on oeis4.)