A290240 The number of unitary untouchable numbers <= 10^n.

5, 5, 9, 75, 862, 9903, 101030, 1028263

Offset

1,1

Comments

The unitary version of A057978. a(5)-a(8) were taken from the paper by Pomerance and Yang.

Links

Table of n, a(n) for n=1..8.

Carl Pomerance and Hee-Sung Yang, Variant of a theorem of Erdős on the sum-of-proper-divisors function, Mathematics of Computation, Vol. 83, No. 288 (2014), pp. 1903-1913.

Crossrefs

Cf. A057978, A063948.

Sequence in context: A336140 A321660 A351292 * A245088 A078560 A331064

Adjacent sequences: A290237 A290238 A290239 * A290241 A290242 A290243

Keyword

nonn,more

Author

Amiram Eldar, Jul 24 2017

Status

approved