login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A124436 a(1)=1, a(n)=p_i^d_i where p_i is i-th prime and d_i is i-th digit of a(n-1). 0
1, 2, 4, 16, 1458, 2918430506250, 7164640537512654203797788776525821310188011060 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Or a(n-1)= decimal encoding of the prime factorization of a(n). Cf. A068633 Let n = p^a*q^b... then a(n) = concatenation paqb..., A067599 Decimal encoding of the prime factorization of n.

LINKS

Table of n, a(n) for n=1..7.

EXAMPLE

a(4)=16, a(5)=2^1 * 3^6 = 1458;

a(6)= 2^1 * 3^4 * 5^5 * 7^8 = 2918430506250.

MATHEMATICA

a[1]=1; id[n_]:=id[n]=IntegerDigits[a[n-1]]; a[n_]:=a[n]= Times@@Table[Prime[i]^id[n][[i]], {i, 1, Length[id[n]]}]; {1, Table[a[n], {n, 2, 7}]}//Flatten

CROSSREFS

Cf. A067599, A068633.

Sequence in context: A194457 A001128 A280890 * A014221 A249760 A271552

Adjacent sequences:  A124433 A124434 A124435 * A124437 A124438 A124439

KEYWORD

base,nonn

AUTHOR

Zak Seidov, Dec 16 2006

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 16 15:51 EDT 2019. Contains 328101 sequences. (Running on oeis4.)