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.

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

Author

David Wasserman, Jan 08 2006

Keywords

• nonn
• tabl
• less

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.

Examples

			a(4, 3) = 3445 because 3445, 3448, 3451 and 3454 each have 8 divisors.
		

Crossrefs

Cf. A006558, A065559, A113456, A113466, A113467, A113468.