A087195 Numbers of the form 1+(1+p)*p^e, p prime and e>0.

7, 13, 25, 31, 37, 49, 57, 97, 109, 133, 151, 183, 193, 307, 325, 381, 385, 393, 553, 751, 769, 871, 973, 993, 1407, 1453, 1537, 1723, 1893, 2257, 2367, 2745, 2863, 2917, 3073, 3541, 3751, 3783, 4557, 5113, 5203, 5403, 6145, 6321, 6973, 7221

Offset: 1

Author

Reinhard Zumkeller, Aug 24 2003

Keywords

• nonn

Comments

a(n) = 1+(1+A025473(k))*A000961(k) for some k>1, this k is unique except for n=2: a(2) = 13 = 1+(1+2)*2^2 = 1+(1+3)*3^1.

Examples

			p=2, e=7: 1+(1+A000040(1))*A000040(1)^7 = 1+(1+2)*2^7 = 1+3*128 = 385 = a(17);
p=7, e=2: 1+(1+A000040(4))*A000040(4)^2 = 1+(1+7)*7^2 = 1+8*49 = 393 = a(18).
		

Crossrefs

Cf. A087196, A008864.