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A337335
a(n) = gcd(A048673(n), 1+A003973(n)).
3
1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 29, 1, 1, 1, 1, 1, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 19, 1, 13, 1, 1, 1, 13, 1, 1, 1
OFFSET
1,10
FORMULA
a(n) = gcd(A048673(n), 1+A003973(n)) = (n) = gcd((1+A003961(n))/2, 1+sigma(A003961(n))).
For all n>= 1, a(A000290(n)) = A337337(n).
PROG
(PARI)
A003961(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
A337335(n) = { my(s=A003961(n)); gcd((1+s)/2, 1+sigma(s)); };
CROSSREFS
Cf. A003961, A003973, A048673, A337337, A337342 (positions where equal to A048673).
Cf. also A336850.
Sequence in context: A260237 A118135 A318671 * A109014 A268357 A321804
KEYWORD
nonn
AUTHOR
Antti Karttunen, Aug 24 2020
STATUS
approved