1,1

If m is in this sequence and 5 doesn't divide m then m is an odd Weird number. There are no other terms up to 2*10^9. Jud McCranie (j.mccranie(AT)comcast.net) wrote: There are no terms between 2*10^9 and 6.5*10^9.

S. Benkoski, "Are All Weird Numbers Even?" Amer. Math. Monthly 79, 774, 1972.

R. K. Guy, "Almost Perfect, Quasi-Perfect, Pseudoperfect, Harmonic, Weird, Multiperfect and Hyperperfect Numbers." B2 in Unsolved Problems in Number Theory, 2nd ed.New York:Springer- Verlag, pp. 45-53, 1994.

C. Rivera, Puzzle 233, www.primepuzzles.net

Eric Weisstein's World of Mathematics, Weird Number

a(1)=8925 because sigma(8925)=2*8925+6 and 8925 is the first odd number that sigma(n)-2n=6.

Do[If[OddQ[n] && DivisorSigma[1, n] - 2n == 6, Print[n]], {n, 2*10^9}]

Cf. A077374, A005101, A005835.

Sequence in context: A134975 A037192 A065235 this_sequence A034589 A144126 A106770

Adjacent sequences: A087164 A087165 A087166 this_sequence A087168 A087169 A087170

hard,more,nonn,bref

Farideh Firoozbakht (f.firoozbakht(AT)sci.ui.ac.ir), Oct 19 2003