A105100 - OEIS

%I #8 Apr 30 2022 14:51:50

%S 41,156,304,462,630,834,1020,1214,1420,1618,1824,2076,2288,2514,2712,

%T 2926,3198,3460,3656,3874,4086,4370,4598,4888,5100,5346,5626,5886,

%U 6126,6332,6580,6836,7146,7386,7678,7848,8208,8560,8762,8962,9258,9498,9696

%N Sum of ordered 3 prime sided prime triangles.

%C An ordered 3 prime sided prime triangle is 6 consecutive primes arranged in an equilateral triangle of the form

%C ...........p(6n-5)

%C .....p(6n-4).....p(6n-3)

%C .p(6n-2)...p(6n-1)......p(6n)

%H Harvey P. Dale, <a href="/A105100/b105100.txt">Table of n, a(n) for n = 1..1000</a>

%e The first 3 prime sided prime triangle

%e 2

%e 3 5

%e 7 11 13

%e adds up to 41, the first entry.

%t Total/@Partition[Prime[Range[300]],6] (* _Harvey P. Dale_, Apr 30 2022 *)

%o (PARI) sumtri3x3(n) = { local(x,j,s); forstep(x=1,n,6, s = prime(x)+prime(x+1)+prime(x+2)+prime(x+3)+prime(x+4)+prime(x+5); print1(s",") ) }

%K easy,nonn

%O 1,1

%A _Cino Hilliard_, Apr 07 2005