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 A027293 Triangular array given by rows: P(n,k) = number of partitions of n that contain k as a part. 25
 1, 1, 1, 2, 1, 1, 3, 2, 1, 1, 5, 3, 2, 1, 1, 7, 5, 3, 2, 1, 1, 11, 7, 5, 3, 2, 1, 1, 15, 11, 7, 5, 3, 2, 1, 1, 22, 15, 11, 7, 5, 3, 2, 1, 1, 30, 22, 15, 11, 7, 5, 3, 2, 1, 1, 42, 30, 22, 15, 11, 7, 5, 3, 2, 1, 1, 56, 42, 30, 22, 15, 11, 7, 5, 3, 2, 1, 1, 77 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS Triangle read by rows in which row n lists the first n partition numbers A000041 in decreasing order. - Omar E. Pol, Aug 06 2011 A027293 * an infinite lower triangular matrix with A010815 (1, -1, -1, 0, 0, 1,...) as the main diagonal the rest zeros = triangle A145975 having row sums = [1, 0, 0, 0,...]. These matrix operations are equivalent to the comment in A010815 stating "when convolved with the partition numbers = [1, 0, 0, 0,...]. [Gary W. Adamson, Oct 25 2008] From Gary W. Adamson, Oct 26 2008: (Start) Row sums = A000070: (1, 2, 4, 7, 12, 19, 30, 45, 67,...) A027293^2 = triangle A146023 (End) 1) It appears that P(n,k) is also the total number of occurrences of k in the last k sections of the set of partitions of n (Cf. A182703). 2) It appears that P(n,k) is also the difference, between n and n-k, of the total number of occurrences of k in all their partitions (Cf. A066633). - Omar E. Pol, Feb 07 2012 Sequence B is called a reverse reluctant sequence of sequence A, if B is triangle array read by rows: row number k lists first k elements of the sequence A in reverse order. Sequence A027293 is the reverse reluctant sequence of A000041. - Boris Putievskiy, Dec 14 2012 LINKS Robert Price, Table of n, a(n) for n = 1..5050 Boris Putievskiy, Transformations Integer Sequences And Pairing Functions arXiv:1212.2732 [math.CO] FORMULA P(n,k) = p(n-k) = A000041(n-k), n>=1, k>=1. - Omar E. Pol, Feb 15 2013 a(n) = A000041(m), where m=(t*t+3*t+4)/2-n, t=floor((-1+sqrt(8*n-7))/2). - Boris Putievskiy, Dec 14 2012 EXAMPLE Triangle begins: 1 1 1 2 1 1 3 2 1 1 5 3 2 1 1 7 5 3 2 1 1 11 7 5 3 2 1 1 15 11 7 5 3 2 1 1 22 15 11 7 5 3 2 1 1 30 22 15 11 7 5 3 2 1 1 42 30 22 15 11 7 5 3 2 1 1 MATHEMATICA f[n_] := Block[{t = Flatten[Union /@ IntegerPartitions@n]}, Table[Count[t, i], {i, n}]]; Array[f, 13] // Flatten t[n_, k_] := PartitionsP[n-k]; Table[t[n, k], {n, 1, 13}, {k, 1, n}] // Flatten (* Jean-François Alcover, Jan 24 2014 *) CROSSREFS Every column of P is A000041. Cf. A145975, A010815. Cf. A000070, A146023. Cf. A182700. Sequence in context: A225640 A194543 A287920 * A104762 A152462 A180360 Adjacent sequences:  A027290 A027291 A027292 * A027294 A027295 A027296 KEYWORD nonn,tabl AUTHOR STATUS approved

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Last modified July 13 11:46 EDT 2020. Contains 335687 sequences. (Running on oeis4.)