A327962 a(1) = 27846; thereafter a(n+1) = a(n) # n, where # is an operation that cycles through division, addition, subtraction and multiplication.

27846, 27846, 27848, 27845, 111380, 22276, 22282, 22275, 178200, 19800, 19810, 19799, 237588, 18276, 18290, 18275, 292400, 17200, 17218, 17199, 343980, 16380, 16402, 16379, 393096

Offset

1,1

Comments

a(26) is not an integer, so we terminate the sequence. This is the longest integer-only sequence of this type.

Links

Table of n, a(n) for n=1..25.

Puzzling StackExchange, What is the next number in the series: 21, 21, 23, 20, 5, 25, 31, 24,?.

Example

a(1) = 27846
a(2) = a(1)/1 = 27846
a(3) = a(2)+2 = 27848
a(4) = a(3)-3 = 27845
a(5) = a(4)*4 = 111380
a(6) = a(5)/5 = 22276

Mathematica

With[{f = {Times, Divide, Plus, Subtract}}, NestWhile[Append[#1, Apply[f[[#3]], {#1[[-1]], #2}]] & @@ {#1, #2, 1 + Mod[#2, 4]} & @@ {#1, Length[#]} &, {27846}, FreeQ[#, Rational] &, 1, Infinity, -1]] (* Michael De Vlieger, Oct 01 2019 *)

Crossrefs

Sequence in context: A058419 A235208 A251494 * A046333 A202403 A206618

Adjacent sequences: A327959 A327960 A327961 * A327963 A327964 A327965

Keyword

nonn,fini

Author

Dmitry Kamenetsky, Oct 01 2019

Status

approved