A351574 Terms of A228058 missing from A347874.

117, 245, 333, 425, 549, 605, 637, 657, 725, 833, 845, 873, 981, 1025, 1053, 1325, 1413, 1421, 1445, 1629, 1737, 1805, 1813, 2009, 2057, 2061, 2169, 2225, 2493, 2525, 2597, 2645, 2817, 2825, 2873, 2925, 2989, 2997, 3033, 3141, 3357, 3425, 3509, 3573, 3577, 3681, 3725, 3789, 3897, 4113, 4205, 4325, 4361, 4693, 4753

Offset

1,1

Comments

Numbers that satisfy Euler's criterion for the odd perfect numbers (A228058), but do not satisfy the criterion specified in A347874.

Links

Table of n, a(n) for n=1..55.

Index entries for sequences related to sigma(n)

Prog

(PARI)
A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
A342926(n) = (A003415(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));
isA347874(n) = ((n%2)&&!isprime(n)&&!(A342926(n)%2)&&!(A342926(2*n)%3));
isA351574(n) = (isA228058(n) && !isA347874(n));

Crossrefs

Setwise difference A228058 \ A347874.

Cf. A000203, A003415.

Sequence in context: A112877 A064180 A050245 * A031174 A146172 A146189

Adjacent sequences: A351571 A351572 A351573 * A351575 A351576 A351577

Keyword

nonn

Author

Antti Karttunen, Feb 23 2022

Status

approved