A199924 Numbers k such that the sum of the largest and the smallest prime divisor of k^2 + 1 equals the sum of the other distinct prime divisors.

948, 1560, 1772, 2153, 2697, 8487, 11293, 12553, 13236, 18065, 32247, 36984, 40452, 43999, 55945, 94536, 100512, 107607, 127224, 134223, 214641, 218783, 366937, 425808, 429855, 595471, 620865, 645327, 757382, 850416, 875784, 1241106, 1330849, 1363977, 1387689

Offset: 1

Author

Michel Lagneau, Nov 12 2011

Keywords

• nonn

Comments

Generalization of A192770 and A192771.

Examples

			2697 is in the sequence because 2697^2 + 1 = 7273810 has five distinct divisors  2, 5, 41, 113, 157 and 157 + 2 = 5 + 41 + 113 = 159.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..200

Crossrefs

Cf. A180278, A192771, A192770.

Programs

Mathematica

Select[Range[1400000],Plus@@((pl=First/@FactorInteger[#^2+1])/2)==pl[[1]]+pl[[-1]]&](* program of Ray Chandler adapted for this sequence - see A199745 *)