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A069789
Smallest k>n such that sigma(n) divides sigma(k).
4
2, 5, 6, 12, 6, 11, 14, 24, 18, 17, 14, 28, 20, 15, 23, 25, 22, 45, 24, 26, 31, 30, 30, 38, 48, 41, 54, 39, 38, 46, 42, 68, 35, 53, 42, 117, 74, 54, 60, 58, 44, 62, 86, 60, 90, 51, 62, 75, 74, 80, 55, 97, 85, 56, 66, 87, 79, 88, 87, 78, 75, 69, 103, 192, 78, 70, 134, 82, 77
OFFSET
1,1
LINKS
MATHEMATICA
a[n_] := Module[{k = n+1, s = DivisorSigma[1, n]}, While[!Divisible[DivisorSigma[1, k], s], k++]; k]; Array[a, 100] (* Amiram Eldar, Jun 03 2022 *)
PROG
(PARI) for(s=1, 80, n=s+1; while(frac(sigma(n)/sigma(s))>0, n++); print1(n, ", "); )
CROSSREFS
Cf. A000203.
Sequence in context: A275522 A110975 A190120 * A332683 A086334 A346759
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, May 01 2002
STATUS
approved