17949434

Appears in sequences

• Numbers k such that the multiplicative group of residues prime to k, M_k, is isomorphic to M_{k+1}.at n=16A003276
• A number n is included in the sequence if and only if the n-th integer from among those positive integers which are coprime to n+1 = the (n+1)-st integer from among those positive integers which are coprime to n.at n=27A139766