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A248147 Table read by rows: n-th row contains all consecutive subsets of the first n primes in their natural order. 5
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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).

LINKS

Reinhard Zumkeller, Rows n = 1..20 of triangle, flattened

EXAMPLE

.  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] ...

PROG

(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]

CROSSREFS

Cf. A151800, A000292, A000217, A248164, A248141.

Sequence in context: A185816 A099427 A059964 * A087458 A052180 A065151

Adjacent sequences:  A248144 A248145 A248146 * A248148 A248149 A248150

KEYWORD

nonn,tabf

AUTHOR

Reinhard Zumkeller, Oct 02 2014

STATUS

approved

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Last modified August 22 12:39 EDT 2017. Contains 290946 sequences.