A226101 Smallest number k such that prime(n) divides the n-th divisor of k.

3, 10, 14, 44, 52, 102, 114, 276, 348, 372, 444, 984, 1032, 1128, 1272, 2124, 2196, 3216, 3408, 4380, 4740, 4980, 5340, 11640, 12120, 12360, 12840, 13080, 13560, 15240, 15720, 24660, 25020, 26820, 27180, 37680, 39120, 40080, 41520, 64440, 65160, 68760, 69480

Offset: 2

Author

Michel Lagneau, May 26 2013

Keywords

• nonn

Examples

			a(9) = 276 because the divisors of 276 are {1, 2, 3, 4, 6, 12, 23, 46, 69, 92, 138, 276}, and prime(9) = 23, the 9th divisor of 276 is 69 and 23 | 69.
		

Crossrefs

Cf. A000040, A027750, A221647.

See A221647 for other sequences giving the smallest number whose n-th divisor satisfies some condition.

Programs

Mathematica

nn = 45; t = Table[0, {nn}]; found = 1; n = 2; While[found < nn, n++; d = Divisors[n]; Do[If[i <= nn && Mod[d[[i]],Prime[i]]==0 && t[[i]] == 0, t[[i]] = n; found++], {i, Length[d]}]]; Rest[t] (* Program from T. D. Noe, adapted for this sequence (see A221647) *)