A292283 Numbers n such that f(g(n)) - g(f(n)) = n where f = A001065 and g = A051953.

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

Links

Table of n, a(n) for n=1..4.

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

Cf. A001065, A051953, A291869, A292208.

Sequence in context: A004974 A251824 A228519 * A265457 A330902 A323803

Adjacent sequences: A292280 A292281 A292282 * A292284 A292285 A292286

Keyword

nonn,more

Author

Altug Alkan, Sep 13 2017

Status

approved