A337202 a(n) = 2*A246277(A047802(n)).

12, 120, 19399380, 195534950863140268380, 1678409980907129617069656971232406858049983380, 1193774258350145889842491509271710921616406416330926349273223856572483463433620

Offset: 0

Author

Antti Karttunen, Aug 19 2020

Keywords

• nonn

Comments

Question: Are there any duplicate terms, not necessarily consecutive? That is, are there two or more terms of A047802 that occur in the same column of array A246278?

Links

• Antti Karttunen, Table of n, a(n) for n = 0..13 (Prepared from the b-file of A047802 provided by Jeppe Stig Nielsen)
• Index entries for sequences computed from indices in prime factorization

Crossrefs

Cf. A047802, A246277, A246278, A336389.

Programs

PARI

A246277(n) = if(1==n, 0, my(f = factor(n), k = primepi(f[1,1])-1); for (i=1, #f~, f[i,1] = prime(primepi(f[i,1])-k)); factorback(f)/2);
A337202(n) = 2*A246277(A047802(n));

Formula

For all n >= 0, a(n) >= A336389(1+n).