cp's OEIS Frontend

A128716 Triangle where the n-th row, of n terms in order, contains consecutive multiples of n. The smallest term of row n is the smallest integer greater than or equal to the largest term of row (n-1), for n >= 2.

%I A128716 #14 Jun 25 2019 01:06:20
%S A128716 1,2,4,6,9,12,12,16,20,24,25,30,35,40,45,48,54,60,66,72,78,84,91,98,
%T A128716 105,112,119,126,128,136,144,152,160,168,176,184,189,198,207,216,225,
%U A128716 234,243,252,261,270,280,290,300,310,320,330,340,350,360,363,374,385,396
%N A128716 Triangle where the n-th row, of n terms in order, contains consecutive multiples of n. The smallest term of row n is the smallest integer greater than or equal to the largest term of row (n-1), for n >= 2.
%C A128716 If we instead had the triangle where the smallest term of row n is the smallest integer strictly greater than the largest term of row (n-1), for n >= 2, then we would have sequence A033291.
%F A128716 T(n,k+1) = T(n,k) + n for 1 <= k < n. T(n,1) = n*ceiling(T(n-1,n-1)/n) for n >= 2. - _R. J. Mathar_, Nov 01 2007
%e A128716 Triangle starts
%e A128716     1;
%e A128716     2,   4;
%e A128716     6,   9,  12;
%e A128716    12,  16,  20,  24;
%e A128716    25,  30,  35,  40,  45;
%e A128716    48,  54,  60,  66,  72,  78;
%e A128716    84,  91,  98, 105, 112, 119, 126;
%e A128716   128, 136, 144, 152, 160, 168, 176, 184;
%e A128716   189, 198, 207, 216, 225, 234, 243, 252, 261;
%p A128716 A128716 := proc(n,k) option remember ; if n = 1 then 1 ; elif k = 1 then n*ceil(A128716(n-1,n-1)/n) ; else A128716(n,k-1)+n ; fi ; end: for n from 1 to 11 do for k from 1 to n do printf("%d,",A128716(n,k)) ; od: od: # _R. J. Mathar_, Nov 01 2007
%Y A128716 Cf. A033291.
%K A128716 easy,nonn,tabl
%O A128716 1,2
%A A128716 _Leroy Quet_, Jun 12 2007
%E A128716 More terms from _R. J. Mathar_, Nov 01 2007