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A307356
a(n) is the numbers of 2's in row n of triangle A307239.
2
0, 0, 1, 0, 2, 2, 3, 0, 2, 0, 2, 2, 8, 6, 5, 0, 2, 2, 7, 8, 13, 12, 13, 8, 9, 6, 11, 8, 11, 8, 7, 0, 4, 2, 7, 10, 21, 20, 29, 24, 25, 22, 27, 24, 27, 24, 23, 16, 19, 14, 17, 20, 27, 28, 35, 24, 23, 22, 25, 22, 25, 16, 13, 0, 6, 12, 23, 32, 43, 44, 57, 56, 57
OFFSET
0,5
LINKS
FORMULA
a(n) <= A048967(n).
a(2^k - 1) = 0 for any k >= 0.
EXAMPLE
The first terms, alongside the corresponding rows in A307239, are:
n a(n) Row n of A307239
-- ---- ------------------------------------------
0 0 1
1 0 1 1
2 1 1 2 1
3 0 1 3 3 1
4 2 1 2 6 2 1
5 2 1 3 2 2 3 1
6 3 1 2 5 2 5 2 1
7 0 1 3 7 7 7 7 3 1
8 2 1 2 10 14 14 14 10 2 1
9 0 1 3 6 6 14 14 6 6 3 1
10 2 1 2 3 6 10 14 10 6 3 2 1
PROG
(PARI) rad(n) = my (p=factor(n)[, 1]~); prod(i=1, #p, p[i])
{ for (r=0, 72, row = vector(r+1, k, if ( k==1||k==r+1, 1, rad(row[k-1]+row[k]))); print1 (sum(k=1, r+1, row[k]==2) ", ")) }
CROSSREFS
Sequence in context: A303545 A306191 A290125 * A091426 A053761 A138067
KEYWORD
nonn
AUTHOR
Rémy Sigrist, Apr 03 2019
STATUS
approved