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A127639
A051731 * A127640, where A127640 = infinite lower triangular matrix with the sequence of primes in the main diagonal and the rest zeros.
5
2, 2, 3, 2, 0, 5, 2, 3, 0, 7, 2, 0, 0, 0, 11, 2, 3, 5, 0, 0, 13, 2, 0, 0, 0, 0, 0, 17, 2, 3, 0, 7, 0, 0, 0, 19, 2, 0, 5, 0, 0, 0, 0, 0, 23, 2, 3, 0, 0, 11, 0, 0, 0, 0, 29, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 31, 2, 3, 5, 7, 0, 13, 0, 0, 0, 0, 0, 37, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 41, 2, 3, 0, 0, 0, 0, 17, 0, 0
OFFSET
1,1
COMMENTS
Row sums = A007445, inverse Mobius transform of the primes: (2, 5, 7, 12, 13, 23, ...)
EXAMPLE
First few rows of the triangle are:
2;
2, 3;
2, 0, 5;
2, 3, 0, 7;
2, 0, 0, 0, 11;
2, 3, 5, 0, 0, 13;
...
MAPLE
A051731 := proc(n, k) if n mod k = 0 then 1 ; else 0 ; fi ; end: A127639 := proc(n, k) A051731(n, k)*ithprime(k) ; end: for n from 1 to 16 do for k from 1 to n do printf("%d, ", A127639(n, k)) ; od ; od ; # R. J. Mathar, Mar 14 2007
CROSSREFS
KEYWORD
nonn,tabl,easy
AUTHOR
Gary W. Adamson, Jan 21 2007
EXTENSIONS
More terms from R. J. Mathar, Mar 14 2007
STATUS
approved