A333801 Numbers k such that A008475(k)+1 = A008475(k+1).

2, 3, 4, 7, 8, 16, 20, 31, 35, 127, 143, 208, 256, 650, 1479, 2464, 2623, 4233, 4345, 5183, 8099, 8191, 9424, 11024, 11919, 12099, 14905, 16159, 20220, 20800, 21716, 22194, 24335, 26123, 27335, 27390, 30457, 34945, 38180, 40425, 52206, 56563, 65536, 67123, 68264

Offset

1,1

Comments

A variation of A064111 and A228126 with unitary prime-power divisors instead of prime divisors.

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

4 is a term since A008475(4) + 1 = 4 + 1 = 5 = A008475(5).

Mathematica

s[1] = 0; s[n_] := Plus @@ (Power @@@ FactorInteger[n]); seq = {}; s1 = 0; Do[s2 = s[n]; If[s1 + 1 == s2, AppendTo[seq, n - 1]]; s1 = s2, {n, 2, 10^5}]; seq

Crossrefs

Cf. A006145, A008475, A039752, A064111, A228126, A331000, A333802.

Sequence in context: A126850 A007497 A126882 * A239973 A281782 A334020

Adjacent sequences: A333798 A333799 A333800 * A333802 A333803 A333804

Keyword

nonn

Author

Amiram Eldar, Apr 05 2020

Status

approved