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A229268

Primes of the form sigma(k) - tau(k), where sigma(k) = A000203(k) and tau(k) = A000005(k).

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

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OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..5000

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 *)

CROSSREFS

Cf. A000005, A000010, A000203, A009087, A023194, A038344, A055813, A062700, A064205, A065608, A141242, A229264, A229266

Sequence in context: A198894 A367798 A222206 * A309068 A015180 A052290

Adjacent sequences: A229265 A229266 A229267 * A229269 A229270 A229271

KEYWORD

nonn

AUTHOR

Paolo P. Lava, Sep 18 2013

EXTENSIONS

More terms from Michel Marcus, Sep 21 2013

STATUS

approved

URL: https://oeis.org/A229268

⇱ A229268 - OEIS