

A122483


Numbers such that (1)Sigma(m)*Sigma(m)= k*UnitaryPhi(m)*m for some integer k.


1



6, 140, 312, 1560, 14384, 18018, 40992, 2337400, 7012200, 11027016, 231402600
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OFFSET

1,1


COMMENTS

If both 2^n3 and 2^n1 are prime them numbers of the form 2^(n1)*(M_n2)*M_n appear on the sequence, where M_n means Mersenne prime.


LINKS

Table of n, a(n) for n=1..11.


EXAMPLE

2^8*7*19*37*73*509, 2^8*5*7*19*37*509, 2^8*5^2*7*19*29*31*37*509, 2^9*3*11*31*1021, 2^9*3*7*11^2*19*31*131*1021, 2^11*3^6*5*7*13*23*137*467*1093*4093, 2^13*3*11*43*127*16381, 2^13*3*7*11^2*19*43*127*131*16381 But between 3*10^7 and them, many terms may lack.


CROSSREFS

Cf. A123124.
Sequence in context: A053467 A090944 A007340 * A123729 A193835 A123728
Adjacent sequences: A122480 A122481 A122482 * A122484 A122485 A122486


KEYWORD

nonn,more


AUTHOR

Yasutoshi Kohmoto, Sep 30 2006


EXTENSIONS

More terms from R. J. Mathar, Oct 01 2006


STATUS

approved



