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

 

Logo

Annual Appeal: Please make a donation to keep the OEIS running. In 2018 we replaced the server with a faster one, added 20000 new sequences, and reached 7000 citations (often saying "discovered thanks to the OEIS").
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A258581 a(1) = 2; for n > 1 if n is even a(n) = gpf(1 + Product_{odd m,m<n}a(m)), while if n is odd a(n) = gpf(1 + Product_{even m,m<n}a(m)). 3
2, 3, 2, 5, 2, 3, 23, 37, 17, 149, 761, 50647, 4799, 411527, 18871308021859, 10312625105789, 17838863896549, 57892815889963361050999657943, 2252973546284243766517, 1849093263449444009859625443689931115519009693 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..20.

Anders Hellström, Sage program

Anders Hellström, Mercury program

PROG

(PARI) gpf(n)=my(v=factor(n)[, 1]); v[#v];

main(size)=my(v=vector(size), i, odd=2, even=1); v[1]=2; for(i=2, size, if(i%2==0, v[i]=gpf(odd+1); even*=v[i], v[i]=gpf(even+1); odd*=v[i])); v;

CROSSREFS

Cf. A000946, A005266.

Sequence in context: A000705 A073751 A319431 * A108501 A166226 A263978

Adjacent sequences:  A258578 A258579 A258580 * A258582 A258583 A258584

KEYWORD

nonn

AUTHOR

Anders Hellström, Jul 15 2015

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 December 13 10:39 EST 2018. Contains 318086 sequences. (Running on oeis4.)