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Message boards : General discussion : Sme question associated with function sigma(n)

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Svetlana U.
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Message 71313 - Posted: 10 Dec 2013 | 11:13:05 UTC

Does anybody know the answer on some questions associated with A231484?

1. Does there exists an odd number n > 1 for which sigma(n),
sigma(sigma(n)) and sigma(sigma(sigma(n))) are odd too?

2. Does there exists a number n > 1 such that sigma(sigma(sigma(n)))/n < 1.5?

3. Note that sigma(3^4) = 11^2. Does there exists another pair (p,r)
such that p is prime, r > 1 and sigma(p^r) = q^s where q is prime and
s > 1?

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Discovered 1 mega primeEliminated 2 conjecture "k"s321 LLR Turquoise: Earned 5,000,000 credits (5,342,838)Cullen LLR Silver: Earned 100,000 credits (158,983)ESP LLR Gold: Earned 500,000 credits (505,527)Generalized Cullen/Woodall LLR Ruby: Earned 2,000,000 credits (2,268,642)PPS LLR Sapphire: Earned 20,000,000 credits (45,725,156)PSP LLR Silver: Earned 100,000 credits (120,541)SoB LLR Amethyst: Earned 1,000,000 credits (1,280,028)SR5 LLR Ruby: Earned 2,000,000 credits (2,649,390)SGS LLR Gold: Earned 500,000 credits (518,356)TRP LLR Silver: Earned 100,000 credits (141,131)Woodall LLR Silver: Earned 100,000 credits (116,405)Cullen/Woodall Sieve (suspended) Silver: Earned 100,000 credits (235,088)PPS Sieve Amethyst: Earned 1,000,000 credits (1,031,526)Sierpinski (ESP/PSP/SoB) Sieve (suspended) Gold: Earned 500,000 credits (500,445)TRP Sieve (suspended) Gold: Earned 500,000 credits (507,938)AP 26/27 Turquoise: Earned 5,000,000 credits (5,078,008)WW Ruby: Earned 2,000,000 credits (2,004,000)GFN Double Bronze: Earned 100,000,000 credits (185,799,544)PSA Silver: Earned 100,000 credits (291,533)
Message 71320 - Posted: 10 Dec 2013 | 16:43:58 UTC - in response to Message 71313.

You could ask at NMBRTHRY list. (google it)
____________
My lucky number is Phi(4, 2^2396029-1)/2.

Message boards : General discussion : Sme question associated with function sigma(n)

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