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Triangle read by rows: R(n,k) = prime(n) mod semiprime(k), 1<=k<=n.
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%I #11 Sep 08 2022 08:45:51

%S 2,3,3,1,5,5,3,1,7,7,3,5,2,1,11,1,1,4,3,13,13,1,5,8,7,3,2,17,3,1,1,9,

%T 5,4,19,19,3,5,5,3,9,8,2,1,23,1,5,2,9,1,14,8,7,4,3,3,1,4,1,3,1,10,9,6,

%U 5,31,1,1,1,7,9,7,16,15,12,11,4,3,1,5,5,1,13,11,20,19,16,15,8,7,6,3,1,7,3,1,13,1,21,18,17,10,9,8,5

%N Triangle read by rows: R(n,k) = prime(n) mod semiprime(k), 1<=k<=n.

%e The triangle starts as

%e 2;

%e 3, 3;

%e 1, 5, 5;

%e 3, 1, 7, 7;

%e 3, 5, 2, 1, 11;

%e 1, 1, 4, 3, 13, 13;

%e 1, 5, 8, 7, 3, 2, 17;

%e 3, 1, 1, 9, 5, 4, 19, 19;

%e 3, 5, 5, 3, 9, 8, 2, 1, 23;

%e 1, 5, 2, 9, 1, 14, 8, 7, 4, 3;

%o (Magma) IsSemiprime:=func< n | &+[ k[2]: k in Factorization(n) ] eq 2 >; splt:=38; T:=[ n: n in [2..splt] | IsSemiprime(n) ]; &cat[ [ NthPrime(n) mod T[k]: k in [1..n] ]: n in [1..#T] ]; // _Klaus Brockhaus_, Dec 02 2010

%Y Cf A001358.

%K nonn,tabl,easy

%O 1,1

%A _Juri-Stepan Gerasimov_, Dec 02 2010