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 A162609 Triangle read by rows in which row n lists n terms, starting with 1, with gaps = n-2 between successive terms. 9
 1, 1, 1, 1, 2, 3, 1, 3, 5, 7, 1, 4, 7, 10, 13, 1, 5, 9, 13, 17, 21, 1, 6, 11, 16, 21, 26, 31, 1, 7, 13, 19, 25, 31, 37, 43, 1, 8, 15, 22, 29, 36, 43, 50, 57, 1, 9, 17, 25, 33, 41, 49, 57, 65, 73, 1, 10, 19, 28, 37, 46, 55, 64, 73, 82, 91, 1, 11, 21, 31, 41, 51, 61, 71, 81 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 COMMENTS Note that the last term of the n-th row is the central polygonal number A002061(n-1). LINKS EXAMPLE Triangle begins:   1;   1,  1;   1,  2,  3;   1,  3,  5,  7;   1,  4,  7, 10, 13;   1,  5,  9, 13, 17, 21;   1,  6, 11, 16, 21, 26, 31; MATHEMATICA Table[NestList[#+(n-2)&, 1, n-1], {n, 20}]//Flatten (* Harvey P. Dale, Oct 23 2017 *) CROSSREFS Cf. A002061, A159797, A159798, A162610, A161611, A162612, A162613. Cf. A060354 (row sums). - R. J. Mathar, Jul 20 2009 Sequence in context: A208814 A230449 A255437 * A194752 A194740 A194762 Adjacent sequences:  A162606 A162607 A162608 * A162610 A162611 A162612 KEYWORD easy,nonn,tabl AUTHOR Omar E. Pol, Jul 09 2009 STATUS approved

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Last modified September 30 12:21 EDT 2020. Contains 337439 sequences. (Running on oeis4.)