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A292283
Numbers n such that f(g(n)) - g(f(n)) = n where f = A001065 and g = A051953.
0
9358, 209662, 2900878, 199550158
OFFSET
1,1
COMMENTS
If 2*p is in this sequence for a prime p, then p + 2 is the arithmetic mean of sigma(p + 1) and phi(p + 3). For the first four terms, primes p such that 2*p is in this sequence are 4679, 104831, 1450439, 99775079.
a(5) > 3*10^10. - Giovanni Resta, Sep 15 2017
EXAMPLE
9358 is a term because A001065(A051953(9358)) - A051953(A001065(9358)) = 11700 - 2342 = 9358.
PROG
(PARI) a001065(n) = sigma(n)-n;
a051953(n) = n-eulerphi(n);
isok(n) = a001065(a051953(n))-a051953(a001065(n))==n;
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Altug Alkan, Sep 13 2017
STATUS
approved