A124436 a(1)=1, a(n)=p_i^d_i where p_i is i-th prime and d_i is i-th digit of a(n-1).

1, 2, 4, 16, 1458, 2918430506250, 7164640537512654203797788776525821310188011060

Offset: 1

Author

Zak Seidov, Dec 16 2006

Keywords

• base
• nonn

Comments

Or a(n-1)= decimal encoding of the prime factorization of a(n). Cf. A068633 Let n = p^a*q^b... then a(n) = concatenation paqb..., A067599 Decimal encoding of the prime factorization of n.

Examples

			a(4)=16, a(5)=2^1 * 3^6 = 1458;
a(6)= 2^1 * 3^4 * 5^5 * 7^8 = 2918430506250.
		

Crossrefs

Cf. A067599, A068633.

Programs

Mathematica

a[1]=1;id[n_]:=id[n]=IntegerDigits[a[n-1]]; a[n_]:=a[n]= Times@@Table[Prime[i]^id[n][[i]],{i,1,Length[id[n]]}]; {1,Table[a[n],{n,2,7}]}//Flatten