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A248147
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Table read by rows: n-th row contains all consecutive subsets of the first n primes in their natural order.
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5
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2, 2, 3, 2, 3, 2, 3, 5, 2, 3, 3, 5, 2, 3, 5, 2, 3, 5, 7, 2, 3, 3, 5, 5, 7, 2, 3, 5, 3, 5, 7, 2, 3, 5, 7, 2, 3, 5, 7, 11, 2, 3, 3, 5, 5, 7, 7, 11, 2, 3, 5, 3, 5, 7, 5, 7, 11, 2, 3, 5, 7, 3, 5, 7, 11, 2, 3, 5, 7, 11, 2, 3, 5, 7, 11, 13, 2, 3, 3, 5, 5, 7, 7, 11
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OFFSET
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1,1
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COMMENTS
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A000292(n) = length of n-th row, whereas A000217(n) = number of all consecutive subsets of numbers 1..n;
T(n,k) = A000040(A248141(n,k)), 1 <= k <= A000292(n).
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LINKS
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Reinhard Zumkeller, Rows n = 1..20 of triangle, flattened
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EXAMPLE
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. 1: 2
. 2: 2,3,2,3
. 3: 2,3,5,2,3,3,5,2,3,5
. 4: 2,3,5,7,2,3,3,5,5,7,2,3,5,3,5,7,2,3,5,7
. 5: 2,3,5,7,11,2,3,3,5,5,7,7,11,2,3,5,3,5,7,5,7,11,2,3,5,7,3,5,7,11,...
rows concatenated from:
. 1: [2]
. 2: [2] [3] [2,3]
. 3: [2] [3] [5] [2,3] [3,5] [2,3,5]
. 4: [2] [3] [5] [7] [2,3] [3,5] [5,7] [2,3,5] [3,5,7] [2,3,5,7]
. 5: [2] [3] [5] [7] [11] [2,3] [3,5] [5,7] [7,11] [2,3,5] [3,5,7] ...
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PROG
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(Haskell)
import Data.List (group)
a248147 n k = a248147_tabf !! (n-1) !! (k-1)
a248147_row n = a248147_tabf !! (n-1)
a248147_tabf = map concat psss where
psss = iterate f [[2]] where
f pss = group (h $ last pss) ++ map h pss
h ws = ws ++ [a151800 $ last ws]
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CROSSREFS
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Cf. A151800, A000292, A000217, A248164, A248141.
Sequence in context: A099427 A059964 A308050 * A087458 A052180 A065151
Adjacent sequences: A248144 A248145 A248146 * A248148 A248149 A248150
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KEYWORD
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nonn,tabf
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AUTHOR
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Reinhard Zumkeller, Oct 02 2014
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STATUS
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approved
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