A116031 sigma(n)-phi(n) and sigma(n)+phi(n) are two palindromes greater than 2.

4, 388, 403, 10010, 11481, 12215, 41242, 42173, 44243, 223261, 223487, 403303, 2302031, 3288877, 3490447, 32605627, 40077553, 40162802, 42311323, 44044043, 117426509, 222613051, 230777581, 232075811, 287772226, 307222207, 327067459

Offset: 1

Author

Giovanni Resta, Feb 13 2006

Keywords

• nonn
• base

Examples

			sigma(3288877)-phi(3288877) = 44444 and
sigma(3288877)+phi(3288877)=6577756.
		

Crossrefs

Cf. A115897, A116030.

Extensions

a(15)-a(27) from Donovan Johnson, Feb 05 2010