A287613 Ulam numbers u such that 5*u is also an Ulam number.

36, 97, 138, 206, 358, 402, 722, 2816, 3205, 3725, 3918, 3962, 5020, 5516, 7461, 8368, 8756, 9193, 9621, 10247, 11219, 11586, 11759, 12365, 12580, 12602, 13164, 13401, 14892, 15820, 17743, 18305, 19644, 20140, 22344, 24785, 29733, 32626, 33276, 34549, 34615, 35888

Offset: 1

Author

Enrique Navarrete, May 27 2017

Keywords

• nonn

Comments

As in the case k=2, these are very scarce Ulam numbers u with the property that k*u is also an Ulam number (see link).

Links

• Enrique Navarrete, Relative Frequencies of Multiples of Ulam Numbers

Crossrefs

Cf. A002858, A068791, A285885, A287612.