A049506 a(1)=1, a(2)=5, a(n+1) = 2^phi(a(1)*a(2)*...*a(n)) - 3.

1, 5, 13, 281474976710653

Offset

1,2

Comments

All terms are of form 2^k - 3 and are relatively prime.

a(5) = 2^253289845471600 =~ 10^76247841084046.2149737362 =~ 1.640490562*10^76247841084046.

References

Posting to Mathematica discussion group mathgroup(AT)smc.vnet.net by Andrzej Kozlowski [ andrzej(AT)tuins.ac.jp ].

Links

Table of n, a(n) for n=1..4.

Crossrefs

Sequence in context: A009143 A240765 A127317 * A069524 A262612 A333025

Adjacent sequences: A049503 A049504 A049505 * A049507 A049508 A049509

Keyword

nonn,easy

Author

Harvey P. Dale

Status

approved