OFFSET
1,2
EXAMPLE
Triangle begins:
n=1: 1;
n=2: 3;
n=3: 5, 6;
n=4: 7;
n=5: 0;
n=6: 11, 14, 15;
n=7: 13, 20;
n=8: 21;
n=9: 17, 22, 30;
...
MATHEMATICA
nmax=30; a={}; For[n=1, n<=nmax, n++, nok=0; For[k=1, k<=n(n+1)/2, k++, If[DivisorSum[k, #&]==n*DivisorSigma[0, k], AppendTo[a, k]; nok=1]]; If[nok==0, AppendTo[a, 0]]]; a (* Stefano Spezia, Jul 20 2022 *)
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
Mohammed Yaseen, Jul 20 2022
STATUS
approved