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A325380
Numbers k in A228058 such that also A001065(k) is in A228058.
3
801, 1377, 1773, 2525, 3725, 4689, 4753, 6309, 6425, 7209, 7677, 8577, 8957, 9477, 11133, 11225, 11493, 11925, 12393, 12429, 12789, 13077, 15381, 15777, 18873, 19269, 19845, 20025, 20629, 21213, 24201, 26073, 26721, 28037, 28989, 29277, 29961, 30037, 30213, 31925, 32553, 33273, 34425, 34677, 36369, 36441, 38725, 39249, 40329
OFFSET
1,1
COMMENTS
If any odd perfect number exists, then it must occur in this sequence.
PROG
(PARI)
A001065(n) = (sigma(n)-n);
isA228058(n) = if(!(n%2)||(omega(n)<2), 0, my(f=factor(n), y=0); for(i=1, #f~, if(1==(f[i, 2]%4), if((1==y)||(1!=(f[i, 1]%4)), return(0), y=1), if(f[i, 2]%2, return(0)))); (y));
k=0; n=0; while(k<100, n++; if(isA228058(n)&&isA228058(A001065(n)), k++; print1(n, ", ")));
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Apr 22 2019
STATUS
approved