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A070010
GCD of consecutive values of sum-of-proper divisors.
1
1, 1, 1, 1, 1, 1, 1, 1, 4, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 11, 1, 1, 1, 6, 2, 1, 1, 1, 1, 1, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 4, 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, 2, 4, 1, 1, 1, 23, 1, 1, 1, 1, 3, 1, 1, 5, 25, 1, 1, 1, 1, 3, 1, 1, 1, 1
OFFSET
1,9
LINKS
FORMULA
a(n) = gcd(A001065(n+1), A001065(n)).
MATHEMATICA
GCD[DivisorSigma[1, n+1]-(n+1), DivisorSigma[1, n]-n]
PROG
(PARI)
A001065(n) = (sigma(n) - n);
A070010(n) = gcd(A001065(n), A001065(1+n)); \\ Antti Karttunen, Oct 05 2017
CROSSREFS
Cf. A000203, A001065; GCD of various consecutive function values: A048586, A057467, A058515, A060778, A060780, A069896.
Sequence in context: A347176 A164561 A178764 * A293768 A046564 A046592
KEYWORD
nonn
AUTHOR
Labos Elemer, Apr 11 2002
STATUS
approved