A337468 a(n) = A080224(A337386(n)).

7, 8, 10, 7, 13, 10, 13, 12, 12, 12, 8, 9, 18, 9, 17, 13, 8, 16, 7, 17, 9, 7, 19, 8, 9, 7, 17, 18, 16, 9, 23, 7, 10, 18, 16, 16, 6, 24, 9, 21, 15, 9, 13, 19, 17, 22, 15, 17, 26, 15, 9, 15, 9, 17, 22, 9, 29, 9, 23, 19, 9, 15, 16, 9, 14, 28, 17, 11, 17, 25, 17, 23, 14, 22, 9, 14, 25, 16, 16, 31, 17, 15, 15, 11, 20

Offset

1,1

Links

Antti Karttunen, Table of n, a(n) for n = 1..20000

Index entries for sequences computed from indices in prime factorization

Index entries for sequences related to sigma(n)

Formula

a(n) = A080224(A337386(n)).

Prog

(PARI)
A003961(n) = { my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
isA337386(n) = { my(x=A003961(n)); (sigma(x)>=2*x); };
A080224(n) = sumdiv(n, d, sigma(d)>2*d)
k=0; for(n=1, 2^12, if(isA337386(n), print1(A080224(n), ", ")));

Crossrefs

Cf. A000203, A003961, A003973, A080224, A337386.

Sequence in context: A048046 A048092 A364601 * A105860 A096677 A120192

Adjacent sequences: A337465 A337466 A337467 * A337469 A337470 A337471

Keyword

nonn

Author

Antti Karttunen, Sep 01 2020

Status

approved