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A325377
a(n) = A001065(A228058(n)), where A001065(n) gives the sum of proper divisors of n.
3
33, 65, 81, 97, 129, 109, 161, 177, 321, 133, 225, 257, 193, 161, 305, 205, 369, 193, 253, 401, 417, 253, 449, 465, 277, 641, 561, 349, 609, 801, 641, 289, 397, 397, 705, 289, 737, 785, 801, 481, 353, 469, 385, 337, 929, 945, 977, 2241, 565, 1041, 1281, 1089, 613, 1121, 637, 1137, 481, 1185, 673, 685, 1265, 709, 1281, 421, 2717, 545, 1601
OFFSET
1,1
LINKS
FORMULA
a(n) = A001065(A228058(n)).
a(n) > A325320(n) for all n.
PROG
(PARI)
up_to = 25000;
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));
A228058list(up_to) = { my(v=vector(up_to), k=0, n=0); while(k<up_to, n++; if(isA228058(n), k++; v[k] = n)); (v); };
v228058 = A228058list(up_to);
A228058(n) = v228058[n];
A001065(n) = (sigma(n)-n);
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Apr 22 2019
STATUS
approved