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A229268
Primes of the form sigma(n) - tau(n), where sigma(n) = A000203(n) and tau(n) = A000005(n).
5
2, 11, 353, 1013, 2333, 16369, 58579, 65519, 123733, 1982273, 7089683, 5778653, 12795053, 10500593, 22586027, 19980143, 24126653, 67108837, 72494713, 90781993, 106199593, 203275951, 164118923, 183105421, 320210549, 259997173, 794091653, 1279963973
OFFSET
1,1
LINKS
FORMULA
a(n) = A000203(A065061(n)) - A000005(A065061(n)). - Michel Marcus, Sep 21 2013
a(n) = A065608(A065061(n)). - Amiram Eldar, Dec 06 2022
EXAMPLE
Second term of A065061 is 8 and sigma(8) - tau(8) = 15 - 4 = 11 is prime.
MAPLE
with(numtheory); P:=proc(q) local a, n; a:= sigma(n)-tau(n); for n from 1 to q do
if isprime(a) then print(a); fi; od; end: P(10^6);
MATHEMATICA
Join[{2}, Select[(DivisorSigma[1, #] - DivisorSigma[0, #]) & /@ (2*Range[20000]^2), PrimeQ]] (* Amiram Eldar, Dec 06 2022 *)
KEYWORD
nonn
AUTHOR
Paolo P. Lava, Sep 18 2013
EXTENSIONS
More terms from Michel Marcus, Sep 21 2013
STATUS
approved