OFFSET
1,2
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..10000
Paul Pollack, Carl Pomerance and Enrique Treviño, Sets of monotonicity for Euler's totient function, preprint. See M↓(n).
Paul Pollack, Carl Pomerance and Enrique Treviño, Sets of monotonicity for Euler's totient function, Ramanujan J. 30 (2013), no. 3, 379--398.
Terence Tao, Monotone non-decreasing sequences of the Euler totient function, arXiv:2309.02325 [math.NT], 2023.
PROG
(Python)
from bisect import bisect
from sympy import totient
def A365737(n):
plist, qlist, c = tuple(-totient(i) for i in range(1, n+1)), [0]*(n+1), 0
for i in range(n):
qlist[a:=bisect(qlist, plist[i], lo=1, hi=c+1, key=lambda x:plist[x])]=i
c = max(c, a)
return c
CROSSREFS
KEYWORD
nonn
AUTHOR
Chai Wah Wu, Sep 17 2023
STATUS
approved