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A127640 Triangle read by rows in which row n contains n-1 0's followed by prime(n).

%I A127640 #14 Feb 28 2025 18:24:25
%S A127640 2,0,3,0,0,5,0,0,0,7,0,0,0,0,11,0,0,0,0,0,13,0,0,0,0,0,0,17,0,0,0,0,0,
%T A127640 0,0,19,0,0,0,0,0,0,0,0,23,0,0,0,0,0,0,0,0,0,29,0,0,0,0,0,0,0,0,0,0,
%U A127640 31,0,0,0,0,0,0,0,0,0,0,0,37,0,0,0,0,0,0,0,0,0,0,0,0,41,0,0,0,0,0,0,0,0,0,0
%N A127640 Triangle read by rows in which row n contains n-1 0's followed by prime(n).
%C A127640 A127641 = this sequence * A051731.
%H A127640 Harvey P. Dale, <a href="/A127640/b127640.txt">Table of n, a(n) for n = 1..1000</a>
%e A127640 First few rows of the triangle are:
%e A127640 2;
%e A127640 0, 3
%e A127640 0, 0, 5;
%e A127640 0, 0, 0, 7;
%e A127640 0, 0, 0, 0, 11;
%e A127640 ...
%p A127640 A127640 := proc(n,m) if m < n then 0; else ithprime(n) ; fi ; end: for n from 1 to 15 do for m from 1 to n do printf("%d,",A127640(n,m)) ; od ; od ; # _R. J. Mathar_, May 19 2007
%t A127640 Table[PadLeft[{Prime[n]},n,0],{n,15}]//Flatten (* _Harvey P. Dale_, Feb 28 2025 *)
%Y A127640 Cf. A127641, A127638, A127639, A051731.
%K A127640 nonn,tabl,easy
%O A127640 1,1
%A A127640 _Gary W. Adamson_, Jan 21 2007
%E A127640 More terms from _R. J. Mathar_, May 19 2007