A082452 a(n)=2n+1 where n is such that A083344(n) is not zero.

45, 75, 117, 147, 189, 195, 225, 231, 245, 315, 325, 345, 363, 385, 405, 441, 483, 495, 507, 525, 561, 567, 585, 595, 645, 663, 675, 693, 715, 735, 765, 775, 777, 795, 819, 845, 847, 867, 875, 891, 931, 945, 957, 975, 1001, 1035, 1071, 1083, 1089, 1095, 1125

Offset

1,1

Links

Table of n, a(n) for n=1..51.

Example

n=22: 2n+1=45, A057643(45)=5520, a(22)=GCD[45,5520]=15 while A066715[45]=3; a(22)=15-3=12.

Mathematica

di[x_] := Apply[LCM, Divisors[x]+1] (*A066715=*)t1=Table[GCD[2*n+1, DivisorSigma[1, 2*n+1]], {n, 1, 2048}]; (*A082457=*)t2=Table[GCD[2*w+1, di[1+2*w]], {w, 1, 2048}]; (*A083344=*)t3=t2-t1; (*A082452=*)1+2*Flatten[Position[Abs[Sign[t3]], 1]];

Crossrefs

Cf. A057643, A066715, A000203, A082457, A083344.

Sequence in context: A259218 A093764 A194426 * A362792 A049104 A226788

Adjacent sequences: A082449 A082450 A082451 * A082453 A082454 A082455

Keyword

nonn

Author

Labos Elemer, Apr 25 2003

Status

approved