OFFSET
1,3
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..10000
PROG
(PARI)
A000203(n) = sigma(n);
A053574(n) = valuation(eulerphi(n), 2);
(Scheme) (define (A286572 n) (* (/ 1 2) (+ (expt (+ (A053574 n) (A000203 n)) 2) (- (A053574 n)) (- (* 3 (A000203 n))) 2)))
(Python)
from sympy import totient, divisor_sigma
def T(n, m): return ((n + m)**2 - n - 3*m + 2)/2
def a007814(n): return 1 + bin(n - 1)[2:].count("1") - bin(n)[2:].count("1")
def a(n): return T(a007814(totient(n)), divisor_sigma(n)) # Indranil Ghosh, May 26 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, May 26 2017
STATUS
approved