A144177 a(n) = b(2n-1)^b(2n) where b(3n+1) = floor(n/9) + 2, b(3n+2) = (n mod 9) + 2, b(3n+3) = b(3n+1)*b(3n+2) for n >= 0.

4, 16, 729, 16, 64, 9765625, 64, 144, 678223072849, 256, 256, 150094635296999121, 1024, 8000, 64, 27, 729, 16777216, 243, 3375, 101559956668416, 2187, 9261, 4722366482869645213696, 19683, 19683, 1000000000000000000000000000000, 16

Offset

1,1

Comments

Old name was: (2*2=4, 2*3=6, 2*4=8, 2*5=10, 2*6=12, 2*7=14, 2*8=16, 2*9=18, 2*10=20, 3*2=6, ...) becomes (abs(2^2, 4^2, 3^6, 2^4, 8^2, 5^10, 2^6, 12^2, 7^14, 2^8, 16^2, 9^18, 2^10, 20^3, 2^6, ...)).

(..., 9*9=81, 9*10=90, 10*2=20, 10*3=30, 10*4=40, 10*5=50, 10*6=60, 10*7=70, 10*8=80, 10*9=90, 10*10=100, 11*2=22, ...) becomes

(abs(..., 9^9, 81^9, 10^90, 10^2, 20^10, 3^30, 10^4, 40^10, 5^50, 10^6, 60^10, 7^70, 10^8, 80^10, 9^90, 10^10, 100^11, 2^22, ...)).

Links

Table of n, a(n) for n=1..28.

Example

  2^2  =       4 = a(1),
  4^2  =      16 = a(2),
  3^6  =     729 = a(3),
  2^4  =      16 = a(4),
  8^2  =      64 = a(5),
  5^10 = 9765625 = a(6), etc.

Mathematica

Power @@@ Partition[Flatten@ Table[{n, k, n k}, {n, 2, 10}, {k, 2, 10}], 2, 2] (* Michael De Vlieger, Oct 24 2022 *)

Prog

(PARI) a(n) = my(k=ceil(n/27), r=n-27*(k-1), v=[]); for(i=2, 10, v=concat(v, [2*k, i, 2*k*i])); for(i=2, 10, v=concat(v, [2*k+1, i, (2*k+1)*i])); v[2*r-1] ^ v[2*r] \\ Jianing Song, Oct 24 2022

Crossrefs

Cf. A144176, A144178.

Sequence in context: A373739 A218644 A013179 * A300315 A361196 A355550

Adjacent sequences: A144174 A144175 A144176 * A144178 A144179 A144180

Keyword

nonn,less

Author

Juri-Stepan Gerasimov, Nov 19 2008

Extensions

More terms from R. J. Mathar, Apr 29 2010

New name from Jianing Song, Nov 01 2022

Status

approved