

A305557


a(1) = a(2) = 1; a(n) = n  a(a(n2))  a(na(n2)) for n > 2.


1



1, 1, 1, 2, 2, 3, 4, 5, 5, 6, 6, 6, 6, 6, 7, 7, 7, 8, 9, 9, 10, 11, 11, 12, 13, 14, 15, 16, 16, 17, 17, 18, 19, 19, 19, 20, 20, 21, 21, 21, 22, 22, 22, 22, 23, 23, 24, 24, 24, 24, 24, 24, 25, 25, 25, 26, 26, 26, 26, 27, 28, 28, 28, 28, 29, 29, 30, 31, 31, 32, 33, 33, 33, 33, 34, 35, 36, 37, 37
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OFFSET

1,4


COMMENTS

Let a_i(n) = n  a_i(a_i(ni))  a_i(na_i(ni)). This sequence is generated by a_2(n) with initial conditions 1, 1.


LINKS

Table of n, a(n) for n=1..79.
Altug Alkan, Proof of basic property


FORMULA

a(n+1)  a(n) = 0 or 1 for all n >= 1 and a(n) hits every positive integer.


MAPLE

a:=proc(n) option remember: if n<3 then 1 else nprocname(procname(n2))procname(nprocname(n2)) fi; end: seq(a(n), n=1..100); # Muniru A Asiru, Jun 26 2018


PROG

(PARI) a=vector(99); a[1]=a[2]=1; for(n=3, #a, a[n] = na[a[n2]]a[na[n2]]); a
(GAP) a:=[1, 1];; for n in [3..100] do a[n]:=na[a[n2]]a[na[n2]]; od; a; # Muniru A Asiru, Jun 26 2018


CROSSREFS

Cf. A005229, A287422, A305845.
Sequence in context: A085972 A136378 A344374 * A099249 A050296 A057062
Adjacent sequences: A305554 A305555 A305556 * A305558 A305559 A305560


KEYWORD

nonn,easy


AUTHOR

Altug Alkan, Jun 21 2018


STATUS

approved



