A058012 Consider the sequence {b(m)} of composite numbers (excluding 1); sequence gives values of b(m) where gcd(m, b(m)) increases.

4, 6, 10, 12, 14, 36, 39, 42, 45, 48, 124, 128, 132, 140, 345, 365, 370, 375, 380, 385, 390, 1086, 1140, 3101, 3122, 8416, 8480, 24309, 24318, 64550, 64560, 64570, 64590, 64600, 64660, 64730, 175208, 175219, 175230, 176616, 480876, 480888, 480948

Offset

1,1

Links

Table of n, a(n) for n=1..43.

Example

a(4) = 12 because twelve is the sixth composite number and gcd(6,12) > gcd(5,10).

Mathematica

r=0; Do[a = GCD[n, n - PrimePi[n] -1]; If[a > r, r = a; Print[n]], {n, 1, 10^6} ]

Crossrefs

Cf. A058011.

Sequence in context: A036438 A338519 A066190 * A026411 A020189 A166986

Adjacent sequences: A058009 A058010 A058011 * A058013 A058014 A058015

Keyword

nonn

Author

Robert G. Wilson v, Nov 13 2000

Extensions

Title corrected by Sean A. Irvine, Jul 17 2022

Status

approved