A182011 a(n) is the smallest number k such that the difference between the greatest prime divisor of k and the sum of the other distinct prime divisors equals n.

6, 2, 3, 21, 5, 55, 7, 33, 22, 39, 11, 85, 13, 51, 34, 57, 17, 115, 19, 69, 46, 203, 23, 145, 1295, 87, 58, 93, 29, 259, 31, 185, 615, 111, 74, 205, 37, 123, 82, 129, 41, 235, 43, 141, 94, 371, 47, 265, 1239, 159, 106, 413, 53, 295, 2345, 177, 118, 183, 59, 469

Offset: 1

Author

Michel Lagneau, Apr 09 2012

Keywords

• nonn

Comments

a(n) = n if n is prime.

Examples

			a(1) = 6 because 6 = 2*3 and 3 - 2 = 1.
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A001221.

Programs

Mathematica

dgpd[n_]:=With[{fi=FactorInteger[n][[;;,1]]},fi[[-1]]-Total[Most[fi]]]; Join[{6},With[{tbl=Table[ {n,dgpd[n]},{n,2500}]},Table[SelectFirst[tbl,#[[2]]==k&],{k,2,60}]][[;;,1]]] (* Harvey P. Dale, Jul 29 2024 *)