OFFSET
1,3
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..10000
PROG
(PARI)
A000010(n) = eulerphi(n);
A001511(n) = (1+valuation(n, 2));
(Scheme) (define (A286568 n) (* (/ 1 2) (+ (expt (+ (A000010 n) (A286357 n)) 2) (- (A000010 n)) (- (* 3 (A286357 n))) 2)))
(Python)
from sympy import divisor_sigma as D, totient
def T(n, m): return ((n + m)**2 - n - 3*m + 2)/2
def a001511(n): return bin(n)[2:][::-1].index("1") + 1
def a286357(n): return a001511(D(n))
def a(n): return T(totient(n), a286357(n)) # Indranil Ghosh, May 26 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, May 26 2017
STATUS
approved