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A113465
Rectangular array read by antidiagonals: a(n, d) is the smallest number that starts an arithmetic progression with common difference d of n numbers with the same number of divisors.
3
1, 2, 1, 33, 3, 1, 242, 3, 2, 1, 11605, 213, 119, 3, 1, 28374, 213, 3445, 3, 2, 1, 171893, 1383, 15026, 111, 77, 5, 1, 1043710445721, 3091, 74783, 201, 8718, 5, 8, 1
OFFSET
1,2
COMMENTS
First two columns are A006558 and A113466. First four rows are A000012, A065559, A113467 and A113468. a(9, 1) is unknown; the rest of the 9th antidiagonal is 8129,88015,201,8718,5,8,3,1.
EXAMPLE
a(4, 3) = 3445 because 3445, 3448, 3451 and 3454 each have 8 divisors.
CROSSREFS
KEYWORD
nonn,tabl,less
AUTHOR
David Wasserman, Jan 08 2006
STATUS
approved