OFFSET
1,2
EXAMPLE
Start with a(1) = 0. The missing numbers are 1 2 3 4 5 6 ...
Multiply the first two, and we get 2, which is therefore a(2).
Cross 1, 2, and 1*2 = 2 off the missing list.
The first two missing numbers are now 3 and 4, so a(3) = 3*4 = 12.
Cross off 3,4,12 from the missing list.
Repeat!
MAPLE
M:=50; A:=[0]; miss:=[seq(n, n=1..M^2)]:
for n from 1 to M do t1:=miss[1]*miss[2]; A:=[op(A), t1];
miss:=[seq(miss[i], i=3..nops(miss))];
miss:=remove('x->x=t1', miss);
od:
A;
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Nov 01 2014
EXTENSIONS
Typo in definition corrected by Douglas Latimer, Nov 01 2014
STATUS
approved