A124873 - OEIS

%I #9 Jun 03 2019 16:32:25

%S 5,17,19,41,43,53,65,99,109,118,147,152,155,161,234,247,271,293,317,

%T 341,480,483,485,499,505,681,725,752,811,850,889,929,1183,1209,1331,

%U 1457,1560,1639,1805,1875,1926,2009,2022,2027,2057,2161,2411,2437,2499,2545

%N Indices of local maxima in sequence A007408.

%C Up to n=200, A007408(n) behaves roughly like 10^(1.3 n) and there are only 14 points (for n < 200) such that A007408(n) >= A007408(n+1); they are all such that A007408(n) > A007408(n+1) < A007408(n+2).

%H Rémy Sigrist, <a href="/A124873/b124873.txt">Table of n, a(n) for n = 1..500</a>

%e a(1) = 5 since k=5 is the smallest index such that A007408(k) >= A007408(k+1).

%p select(n->A007408(n)>=A007408(n+1),[$1..200]);

%o (PARI) v=s=0; for (n=1, 2546, if (v>=v=numerator(s+=1/n^3), print1 (n-1", "))) \\ _Rémy Sigrist_, Jun 03 2019

%Y Cf. A007408.

%K hard,nonn

%O 1,1

%A _M. F. Hasler_, Nov 11 2006

%E More terms from _Rémy Sigrist_, Jun 03 2019