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A065061 Numbers n such that sigma(n) - tau(n) is a prime. 4
3, 8, 162, 512, 1250, 8192, 31250, 32768, 41472, 663552, 2531250, 3748322, 5120000, 6837602, 7558272, 8000000, 15780962, 33554432, 35701250, 42762752, 45334242, 68024448, 75031250, 78125000, 91125000, 137149922, 243101250, 512000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..28.

MAPLE

with(numtheory);

P:=proc(q) local n; for n from 1 to q do

if isprime(sigma(n)-tau(n)) then print(n); fi; od; end: P(10^6);  # Paolo P. Lava, Sep 18 2013

MATHEMATICA

Do[ If[ PrimeQ[ DivisorSigma[1, n] - DivisorSigma[0, n]], Print[n]], {n, 1, 10^7}]

PROG

(PARI) { n=0; for (m=1, 10^9, if (isprime(sigma(m) - numdiv(m)), write("b065061.txt", n++, " ", m); if (n==100, return)) ) } \\ Harry J. Smith, Oct 05 2009

CROSSREFS

I.e. A065608(n) is prime. Cf. A064205.

Cf. A000005, A000203, A023194, A038344, A055813, A062700, A115919, A141242, A229264 - A229266, A229268

Sequence in context: A289884 A076147 A132563 * A007159 A081466 A092592

Adjacent sequences:  A065058 A065059 A065060 * A065062 A065063 A065064

KEYWORD

nonn

AUTHOR

Jason Earls, Nov 06 2001

EXTENSIONS

a(17)-a(28) from Harry J. Smith, Oct 05 2009

STATUS

approved

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Last modified November 21 14:18 EST 2019. Contains 329371 sequences. (Running on oeis4.)