1,1

A123857[n] = {4,8,16,32,38,64,128,205,256,316,512,736,1024,2048,...} are the nonprime numbers n that divide A123855[n-1] = Sum[ Sum[ Prime[i]^j, {i,1,n-1}], {j,1,n-1}]. Corresponding indices n such that a(k) = A123857[n] are n = {5,8,10,12,...}. The next a(n) if it exists is greater than 3000.

Cf. A123857, A123856, A123855.

Sequence in context: A100168 A137022 A005910 this_sequence A020870 A007229 A039685

Adjacent sequences: A124235 A124236 A124237 this_sequence A124239 A124240 A124241

hard,more,nonn

Alexander Adamchuk (alex(AT)kolmogorov.com), Oct 22 2006