A378735 Greatest non-abundant divisor of the n-th abundant number.

6, 9, 10, 8, 15, 9, 10, 21, 16, 27, 28, 15, 33, 35, 9, 39, 16, 28, 44, 45, 32, 50, 51, 52, 27, 28, 57, 15, 63, 44, 69, 35, 16, 75, 52, 32, 81, 28, 87, 44, 45, 93, 64, 98, 99, 50, 68, 52, 105, 27, 110, 111, 32, 76, 117, 16, 123, 63, 129, 130, 44, 135, 136, 92, 35, 141, 32, 147, 75, 152, 153, 154, 52, 159, 64, 81, 165

Offset: 1

Author

Antti Karttunen, Dec 06 2024

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..20000

Crossrefs

Cf. A005101, A294935, A378665.

Cf. also A378736 and the points of differences A378737.

Programs

PARI

A294935(n) = (sigma(n)<=(2*n));
A378665(n) = { fordiv(n,d,if(A294935(n/d), return(n/d))); (1); };
k=0; n=0; while(k<105, n++; if(!A294935(n), k++; print1(A378665(n),", ")));

Formula

a(n) = A378665(A005101(n)).

a(n) >= A378736(n).