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A327856
The upper left triangular section of square array A091255, read by rows.
2
1, 1, 2, 1, 1, 3, 1, 2, 1, 4, 1, 1, 3, 1, 5, 1, 2, 3, 2, 3, 6, 1, 1, 1, 1, 1, 1, 7, 1, 2, 1, 4, 1, 2, 1, 8, 1, 1, 3, 1, 3, 3, 7, 1, 9, 1, 2, 3, 2, 5, 6, 1, 2, 3, 10, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 1, 2, 3, 4, 3, 6, 1, 4, 3, 6, 1, 12, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 13, 1, 2, 1, 2, 1, 2, 7, 2, 7, 2, 1, 2, 1, 14
OFFSET
1,3
FORMULA
A(n,k) = A091255(n,k), with k in range 1 .. n.
a(A000217(n)) = n.
EXAMPLE
The triangular table starts as:
1,
1, 2,
1, 1, 3,
1, 2, 1, 4,
1, 1, 3, 1, 5,
1, 2, 3, 2, 3, 6,
1, 1, 1, 1, 1, 1, 7,
1, 2, 1, 4, 1, 2, 1, 8,
1, 1, 3, 1, 3, 3, 7, 1, 9,
1, 2, 3, 2, 5, 6, 1, 2, 3, 10,
...
PROG
(PARI)
up_to = 105;
A091255sq(a, b) = fromdigits(Vec(lift(gcd(Pol(binary(a))*Mod(1, 2), Pol(binary(b))*Mod(1, 2)))), 2);
A327856list(up_to) = { my(v = vector(up_to), i=0); for(a=1, oo, for(col=1, a, i++; if(i > up_to, return(v)); v[i] = A091255sq(a, col))); (v); };
v327856 = A327856list(up_to);
A327856(n) = v327856[n];
CROSSREFS
Sequence in context: A050873 A324668 A128221 * A175488 A309914 A364911
KEYWORD
nonn,tabl
AUTHOR
Antti Karttunen, Sep 28 2019
STATUS
approved