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 A131432 Triangle read by rows: (A000012 * A131431) + (A131431 * A000012) - A000012 as infinite lower triangular matrices. 2
 1, 4, 7, 7, 10, 13, 10, 13, 16, 19, 13, 16, 19, 22, 25, 16, 19, 22, 25, 28, 31, 19, 22, 25, 28, 31, 34, 37, 22, 25, 28, 31, 34, 37, 40, 43, 25, 28, 31, 34, 37, 40, 43, 46, 49, 28, 31, 34, 37, 40, 43, 46, 49, 52, 55, 31, 34, 37, 40, 43, 46, 49, 52, 55, 58, 61, 34, 37, 40, 43, 46, 49, 52, 55, 58, 61, 64, 67 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Left border = A016777, (1, 4, 7, 10, 13, ...). Right border = A016921: (1, 7, 13, 19, 25, ...). Row sums = A051682, 11-gonal numbers: (1, 11, 30, 58, 95, ...). LINKS Table of n, a(n) for n=0..77. EXAMPLE First few rows of the triangle: 1; 4, 7; 7, 10, 13; 10, 13, 16, 19; 13, 16, 19, 22, 25; 16, 19, 22, 25, 28, 31; 19, 22, 25, 28, 31, 34, 37; ... CROSSREFS Cf. A016777, A051682, A131431, A016921. Sequence in context: A159919 A310929 A310930 * A088744 A168074 A061891 Adjacent sequences: A131429 A131430 A131431 * A131433 A131434 A131435 KEYWORD nonn,tabl AUTHOR Gary W. Adamson, Jul 10 2007 EXTENSIONS a(28) ff. corrected and more terms from Georg Fischer, Jun 05 2023 STATUS approved

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Last modified April 20 22:14 EDT 2024. Contains 371848 sequences. (Running on oeis4.)