OFFSET
0,2
COMMENTS
A226957(a(n)) = n.
Is this a subset of A168264? - Ralf Stephan, Jul 04 2013
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 0..347
MATHEMATICA
a[0]=1; a[n_]:= a[n]=Prime[n]*LCM[a[n - 1], Prime[n] -1];
Table[a[i], {i, 1, 18}]
PROG
(PARI) a(n)=if(n, my(v=primes(n), e=vector(n, i, 1), f, j); forprime(p=2, v[n], f=factor(p-1); for(i=1, #f~, if(f[i, 2]>1, j=primepi(f[i, 1]); e[j]=max(e[j], f[i, 2])))); prod(i=1, n, v[i]^e[i]), 1) \\ Charles R Greathouse IV, Jun 28 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
José María Grau Ribas, Jun 24 2013
STATUS
approved