OFFSET
1,1
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..25000
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