A237522 Numbers k such that phi(k) + sigma(k) = reversal(k) - 1.

25, 165261124, 1698757933

Offset: 1

Author

Giovanni Resta, Feb 08 2014

Keywords

• base
• nonn
• bref
• more

Comments

a(4), if it exists, is larger than 10^13.

Examples

			k = 165261124 is a term, because phi(k) = 67233600, sigma(k) = 353928960 and 67233600 + 353928960 = 421162561 - 1, where 421162561 is the reversal of 165261124.
		

Crossrefs

Cf. A000010, A000203, A004086.

Cf. A070272, A230004, A230005, A230006, A230019, A136544, A237521.