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 A171239 Triangle read by rows extracted from convolution product (1,2,3,...) * A002865: (1,1,2,2,4,4,7,8,...) 2
 1, 1, 2, 2, 2, 3, 2, 4, 3, 4, 4, 4, 6, 4, 5, 4, 8, 6, 8, 5, 6, 7, 8, 12, 8, 10, 6, 7, 8, 14, 12, 16, 10, 12, 7, 8, 8, 14, 12, 16, 10, 12, 7, 8, 12, 16, 21, 16, 20, 12, 14, 8, 9, 14, 24, 24, 28, 20, 24, 14, 10, 9, 10 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Row sums = A058682 starting (1, 3, 7, 13, 23, 37, 58, 87,...). LINKS Table of n, a(n) for n=1..63. FORMULA Triangle read by rows, ascending diagonals of an array formed by the product of (1,2,3,...) and (1,1,2,2,4,4,7,8,12,...). EXAMPLE The triangle = upward sloping diagonals of multiplication table: . 1,..2,..3,..4,..5,..6,..7,... 1,..2,..3,..4,..5,..6,..7,... 2,..4,..6,..8,.10,.12,.14,... 2,..4,..6,..8,.10,.12,.14,... ... First few rows of the triangle = . 1; 1, 2; 2, 2, 3; 2, 4, 3, 4; 4, 4, 6, 4, 5; 4, 8, 6, 8, 5, 6; 7, 8, 12, 8, 10, 6, 7; 8, 14, 12, 16, 10, 12, 7, 8; 12, 16, 21, 16, 20, 12, 14, 8, 9; 14, 24, 24, 28, 20, 24, 14, 10, 9, 10; 21, 28, 36, 32, 35, 24, 28, 16, 18, 10, 11; 24, 42, 42, 48, 40, 42, 28, 32, 18, 20, 11, 12; 34, 48, 63, 56, 60, 48, 49, 32, 36, 20, 22, 12, 13; 41, 68, 72, 84, 70, 72, 56, 56, 36, 40, 22, 24, 13, 14; ... CROSSREFS Cf. A002865, A058682 Sequence in context: A125749 A014085 A248891 * A029210 A321909 A346598 Adjacent sequences: A171236 A171237 A171238 * A171240 A171241 A171242 KEYWORD nonn,tabl AUTHOR Gary W. Adamson, Dec 05 2009 STATUS approved

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Last modified April 14 10:04 EDT 2024. Contains 371657 sequences. (Running on oeis4.)