A128649 Numbers m such that A128646(m) = A128648(m).

1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 16, 17, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 65, 66, 71, 72, 73, 74, 75, 76, 77, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 539, 540, 541, 542, 543, 600, 601, 602, 603, 604, 605, 606, 607, 608, 609, 610

Offset: 1

Author

Alexander Adamchuk, Mar 18 2007

Keywords

• nonn

Comments

Terms of this sequence are 1..5, 7..11, 14..17, 21..35, 65..66, 71..77, 81..93, 539..543, 600..639, 644..650, 707..818, 1152..1185, 4502..4577, 4601..4823, 4893..5003, 7483..7633, ...

Links

• Eric Weisstein's World of Mathematics, Prime Sums

Crossrefs

Cf. A128648 (denominator(Sum_{k=1..n} (-1)^(k+1)/(prime(k)-1))).

Cf. A128646 (denominator(Sum_{k=1..n} 1/(prime(k)-1))).

Cf. A128647, A120271, A119686, A006093, A000040.

Programs

Mathematica

f=0;g=0;Do[p=Prime[n];f=f+1/(p-1);g=g+(-1)^(n+1)*1/(p-1);kf=Denominator[f];kg=Denominator[g];If[Equal[kf,kg],Print[n]],{n,1,10000}]