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 A249055 a(1)=0; the next term is always the product of the two smallest numbers not yet in the sequence and which have not yet been used. 1
 0, 2, 12, 30, 56, 90, 143, 210, 272, 342, 420, 506, 600, 702, 812, 992, 1122, 1260, 1406, 1560, 1722, 1892, 2070, 2256, 2450, 2652, 2862, 3135, 3422, 3660, 3906, 4160, 4422, 4692, 4970, 5256, 5550, 5852, 6162, 6480, 6806, 7140, 7482, 7832, 8372, 8742, 9120, 9506, 9900 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Suggested by A075336 and A249406. LINKS 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 Cf. A075326, A000045, A249406, A000304, A000301. Sequence in context: A067348 A002939 A118239 * A127118 A259127 A296257 Adjacent sequences:  A249052 A249053 A249054 * A249056 A249057 A249058 KEYWORD nonn AUTHOR N. J. A. Sloane, Nov 01 2014 EXTENSIONS Typo in definition corrected by Douglas Latimer, Nov 01 2014 STATUS approved

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Last modified December 12 14:43 EST 2018. Contains 318076 sequences. (Running on oeis4.)