OFFSET
1,2
COMMENTS
For all n (except for n = 2) gcd(A008332(n), prime(n)) = 1. - _Lechoslaw Ratajczak_, Aug 22 2018
REFERENCES
Yu. V. Linnik. The dispersion method in binary additive problems, Izdat. Leningrad Univ., Leningrad, 1961.
József Sándor, Dragoslav S. Mitrinovic and Borislav Crstici, Handbook of Number Theory I, Springer Science & Business Media, 2005, Chapter III, p. 87.
LINKS
Michel Marcus, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Vincenzo Librandi)
FORMULA
MAPLE
for i from 1 to 500 do if isprime(i) then print(sigma(i-1)); fi; od;
MATHEMATICA
Table[DivisorSigma[1, Prime[n] - 1], {n, 80}] (* _Vincenzo Librandi_, Aug 20 2018 *)
PROG
(PARI) a(n) = sigma(prime(n)-1); \\ _Michel Marcus_, Aug 19 2018
(Magma) [DivisorSigma(1, NthPrime(n)-1): n in [1..60]]; // _Vincenzo Librandi_, Aug 20 2018
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
_N. J. A. Sloane_.
EXTENSIONS
Offset corrected by _Michel Marcus_, Aug 20 2018
STATUS
approved