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 A131507 2n+1 appears n+1 times. 9
 1, 3, 3, 5, 5, 5, 7, 7, 7, 7, 9, 9, 9, 9, 9, 11, 11, 11, 11, 11, 11, 13, 13, 13, 13, 13, 13, 13, 15, 15, 15, 15, 15, 15, 15, 15, 17, 17, 17, 17, 17, 17, 17, 17, 17, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Sum of terms of row n is (n+1)*(2n+1) = A000384(n+1). - Michel Marcus, Feb 02 2014 Where records occur give A000217. - Omar E. Pol, Nov 05 2015 LINKS Reinhard Zumkeller, Rows n = 0..125 of triangle, flattened FORMULA a(n) = 2*floor(sqrt(2n+1)+1/2) - 1. - Ridouane Oudra, Oct 20 2019 EXAMPLE As a triangle, the sequence starts: 1; 3, 3; 5, 5, 5; 7, 7, 7, 7; 9, 9, 9, 9, 9; ... MAPLE seq(2*floor(sqrt(2*n+1)+1/2)-1, n=0..70); # Ridouane Oudra, Oct 20 2019 MATHEMATICA Table[2 n + 1, {n, 0, 11}, {n + 1}] // Flatten (* Michael De Vlieger, Nov 05 2015 *) PROG (Haskell) a131507 n k = a131507_tabl !! n !! k a131507_row n = a131507_tabl !! n a131507_tabl = zipWith (\$) (map replicate [1..]) [1, 3 ..] a131507_list = concat a131507_tabl -- Reinhard Zumkeller, Jul 12 2014, Mar 18 2011 (Chipmunk BASIC v3.6.4(b8)) # http://www.nicholson.com/rhn/basic/ for n=1 to 23 step 2 for j=1 to n  step 2 print str\$(n)+", "; next j : next n : print end # Jeremy Gardiner, Feb 02 2014 CROSSREFS Cf. A000217, A002024, A003056, A005408. Cf. A001650. Sequence in context: A035158 A196172 A123313 * A203998 A257371 A075260 Adjacent sequences:  A131504 A131505 A131506 * A131508 A131509 A131510 KEYWORD nonn,tabl AUTHOR Paul Curtz, Aug 13 2007 STATUS approved

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Last modified April 13 10:24 EDT 2021. Contains 342935 sequences. (Running on oeis4.)