A072011 Numbers k such that A072010(k) = k.

1, 2, 4, 8, 16, 32, 35, 64, 70, 128, 140, 256, 280, 323, 512, 560, 646, 899, 1024, 1120, 1225, 1292, 1763, 1798, 2048, 2240, 2450, 2584, 3526, 3596, 4096, 4480, 4900, 5168, 7052, 7192, 8192, 8960, 9800, 10336, 10403, 11305

Offset

1,2

Comments

If A072010(n) = n then also A072010(n*3^i) = n and A072010(n*2^j) = n*2^j.

For m=(4*k+1)*(4*k+3), product of twin prime pairs: A072010(m) = m, as well as for values m in the free monoid generated by the range of A071697.

Links

Amiram Eldar, Table of n, a(n) for n = 1..5000

Example

395675 is a term as f(395675) = f(323*1225) = f((17*19)*(5*7)^2) = f(17*19)*(f(5*7))^2 = f(17)*f(19)*(f(5)*f(7))^2 = 19*17*(7*5)^2 = 323*1225 = 395675 for f = A072010.

Crossrefs

Cf. A002144, A002145, A071695, A071696, A071697, A072010.

Sequence in context: A221467 A337696 A045603 * A068535 A272034 A356382

Adjacent sequences: A072008 A072009 A072010 * A072012 A072013 A072014

Keyword

nonn

Author

Reinhard Zumkeller, Jun 05 2002

Status

approved