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 A278447 Irregular triangle read by rows in which row n lists the semiperimeters of the parts of the symmetric representation of sigma(n). 1
 2, 4, 3, 3, 8, 4, 4, 12, 5, 5, 16, 6, 4, 6, 10, 10, 7, 7, 24, 8, 8, 13, 13, 9, 8, 9, 32 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS FORMULA a(n) = A279160(n)/2. EXAMPLE Triangle begins: 2; 4; 3, 3; 8; 4, 4; 12; 5, 5; 16; 6, 4, 6; 10, 10; 7, 7; 24; 8, 8; 13, 13; 9, 8, 9; 32; ... For n = 9 the symmetric representation of sigma(9) = 13 has three parts of areas 5, 3, 5 respectively. The perímeters of the parts are 12, 8 and 12, so the 9th row of triangle lists the semiperimeters: 6, 4, 6. CROSSREFS Row sums give A244363. Cf. A237271 gives the row lengths. Cf. A000203, A196020, A236104, A235791, A237270, A237591, A237593, A245092, A262626, A279160. Sequence in context: A303354 A330256 A227418 * A235590 A069655 A353706 Adjacent sequences: A278444 A278445 A278446 * A278448 A278449 A278450 KEYWORD nonn,tabf,more AUTHOR Omar E. Pol, Dec 07 2016 STATUS approved

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Last modified February 6 05:26 EST 2023. Contains 360097 sequences. (Running on oeis4.)