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1, 14, 22, 28, 44, 46, 56, 88, 92, 94, 112, 118, 166, 176, 184, 188, 214, 224, 236, 332, 334, 352, 358, 368, 376, 428, 448, 454, 472, 526, 664, 668, 694, 704, 716, 718, 736, 752, 766, 856, 896, 908, 934, 944, 958, 1006, 1052, 1126, 1174, 1328, 1336, 1388, 1408, 1432, 1436, 1438, 1472
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internal format)
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OFFSET
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1,2
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COMMENTS
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Except for a(1) every element is either twice a prime or twice a previous element.
Primes obtained when a term is divided by 2 are of the form 4k + 3, k > 0.
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LINKS
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MAPLE
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isA318929 := proc(n)
simplify(isA300216(n) and isA306146(n)) # reuses code of the other seqs.
end proc:
for n from 1 to 1500 do
if isA318929(n) then
printf("%d, ", n) ;
end if;
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PROG
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(PARI)
is300216(k) = vecsort(factor(k)[, 2]) == vecsort(factor(eulerphi(k))[, 2]);
a023900(n) = sumdivmult(n, d, d*moebius(d));
is306146(n) = sdm = a023900(n); if(sdm < 0, return(0), sdmphi = a023900(eulerphi(n)); eulerphi(sdm) == sdmphi);
isok(n) = is300216(n) && is306146(n); \\ Michel Marcus, Sep 13 2018
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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