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A359625
Least number m such that denominator(sigma(m)/(m+1)) = n, or zero if no such m exists.
1
2, 1, 8, 95, 4, 143, 6, 63, 26, 9, 10, 16415, 12, 111, 44, 255, 16, 273023, 18, 159, 62, 175, 22, 575, 74, 25, 80, 671, 28, 3599, 30, 511, 395, 441, 34, 5183, 36, 303, 116, 8639, 40, 163295, 42, 1055, 134, 101567, 46, 19191876318719, 48, 49, 152, 415, 52, 3887
OFFSET
1,1
COMMENTS
First occurrence of n in A339966.
LINKS
Martin Ehrenstein, Table of n, a(n) for n = 1..10000 (first 1000 terms, except for n = 48, from Michel Marcus)
FORMULA
n | (a(n) + 1). - David A. Corneth, Jan 12 2023
PROG
(PARI) a(n) = my(k=1); while (denominator(sigma(k)/(k+1)) != n, k++); k;
(PARI) a(n) = if(n == 1, return(2)); my(k=n-1); while (denominator(sigma(k)/(k+1)) != n, k+=n); k; \\ David A. Corneth, Jan 12 2023
CROSSREFS
Cf. A162657 (analog for sigma(m)/m), A339966.
Cf. A063906 (sigma(m)/(m+1) = 3/2)
Sequence in context: A239444 A224090 A013327 * A009349 A334254 A230582
KEYWORD
nonn
AUTHOR
Michel Marcus, Jan 07 2023
EXTENSIONS
a(48)-a(54) from Martin Ehrenstein, Jul 23 2023
STATUS
approved