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A256015
Triangle read by rows: n-th row contains all distinct primes which are representable as the sum of some subset of the set of first n primes.
3
2, 2, 3, 5, 2, 3, 5, 7, 2, 3, 5, 7, 17, 2, 3, 5, 7, 11, 13, 17, 19, 23, 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 41, 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67
OFFSET
1,1
COMMENTS
A066028(n) = T(n,A108018(n)).
LINKS
EXAMPLE
. 1: 2 |
. 2: 2 3 | 5
. 3: 2 3 5 | 7
. 4: 2 3 5 7 | 17
. 5: 2 3 5 7 11 | 13 17 19 23
. 6: 2 3 5 7 11 13 | 17 19 23 29 31 41
. 7: 2 3 5 7 11 13 17 | 19 23 29 31 37 41 43 47 53
. 8: 2 3 5 7 11 13 17 19 | 23 29 31 37 41 43 47 53 59 61 67 .
PROG
(Haskell)
import Data.List (subsequences, nub, sort)
a256015 n k = a256015_tabf !! (n-1) !! (k-1)
a256015_row n = a256015_tabf !! (n-1)
a256015_tabf = map (sort . filter ((== 1) . a010051') . nub .
map sum . tail . subsequences) (tail $ inits a000040_list)
CROSSREFS
Cf. A010051, A000040, A108018 (row lengths), A066028 (right edge).
Sequence in context: A140183 A280408 A130725 * A138117 A175908 A152430
KEYWORD
nonn,tabf
AUTHOR
Reinhard Zumkeller, Jun 01 2015
STATUS
approved