A083793 - OEIS

%I #11 Mar 09 2018 20:55:03

%S 3,15,22,34,35,39,45,58,76,86,87,94,95,99,117,119,123,134,136,142,143,

%T 146,148,159,172,178,202,203,206,214,215,218,219,231,245,254,286,297,

%U 299,302,303,327,333,335,376,382,388,394,395,430,435,446,447,454,482

%N Numbers n such that n and n-1 have the same prime signature. Numbers not included in A083792.

%H Alois P. Heinz, <a href="/A083793/b083793.txt">Table of n, a(n) for n = 1..20000</a>

%p s:= n-> sort(map(i-> i[2], ifactors(n)[2])):

%p a:= proc(n) option remember; local k; for k from

%p       1+a(n-1) while s(k)<>s(k-1) do od; k

%p     end: a(0):=1:

%p seq(a(n), n=1..60);  # _Alois P. Heinz_, Mar 09 2018

%t PrimeFactorExponents[n_] := Flatten[ Table[ # [[2]], {1}] & /@ FactorInteger[n]]; Select[ Range[3, 543], PrimeFactorExponents[ # ] == PrimeFactorExponents[ # - 1] & ]

%Y Cf. A083792.

%K nonn

%O 1,1

%A _Amarnath Murthy_, May 07 2003

%E Corrected and extended by _James A. Sellers_, May 19, 2003

%E Some terms corrected by _Alois P. Heinz_, Mar 09 2018