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%I #15 Jan 08 2016 14:29:00
%S 1,2,1,3,1,4,2,1,5,2,1,6,3,1,1,7,3,1,1,8,4,2,1,9,4,2,1,10,5,2,1,1,11,
%T 5,2,1,1,12,6,3,2,1,1,13,6,3,2,1,1,14,7,3,2,1,1,15,7,3,2,1,1,16,8,4,2,
%U 1,1,1,17,8,4,2,1,1,1,18,9,4,3,1,1,1,1
%N Irregular triangle read by rows: T(n,k) = floor(n/(prime(k)-1)), n>=1, 1 <= k <= pi(n+1), where pi is A000720.
%H H. T. Davis, <a href="/A002443/a002443.pdf">Tables of the Mathematical Functions</a>, Vols. 1 and 2, 2nd ed., 1963, Vol. 3 (with V. J. Fisher), 1962; Principia Press of Trinity Univ., San Antonio, TX. [Annotated scan of pages 204-208 of Volume 2.] See Table 1 on page 205.
%e Triangle begins:
%e [1]
%e [2, 1]
%e [3, 1]
%e [4, 2, 1]
%e [5, 2, 1]
%e [6, 3, 1, 1]
%e [7, 3, 1, 1]
%e [8, 4, 2, 1]
%e [9, 4, 2, 1]
%e [10, 5, 2, 1, 1]
%e [11, 5, 2, 1, 1]
%e [12, 6, 3, 2, 1, 1]
%e [13, 6, 3, 2, 1, 1]
%e [14, 7, 3, 2, 1, 1]
%e ...
%p with(numtheory);
%p f:=n->[seq(floor(n/(ithprime(i)-1)),i=1..pi(n+1))];
%p for n from 1 to 20 do lprint(f(n)); od:
%Y Cf. A000720, A002443, A002444, A266743.
%K nonn,tabf
%O 1,2
%A _N. J. A. Sloane_, Jan 08 2016
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