The OEIS is supported by the many generous donors to the OEIS Foundation.

 Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”). Other ways to Give
 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A111290 a(1)=1, a(n) = n + (sum of distinct primes dividing a(n-1)). 1
 1, 2, 5, 9, 8, 8, 9, 11, 20, 17, 28, 21, 23, 37, 52, 31, 48, 23, 42, 32, 23, 45, 31, 55, 41, 67, 94, 77, 47, 77, 49, 39, 49, 41, 76, 57, 59, 97, 136, 59, 100, 49, 50, 51, 65, 64, 49, 55, 65, 68, 70, 66, 69, 80, 62, 89, 146, 133, 85, 82, 104, 77, 81, 67, 132, 82, 110, 86, 114, 94 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Harvey P. Dale, Table of n, a(n) for n = 1..1000 EXAMPLE a(10) = 10 + (sum of distinct primes dividing 20) = 10 + 2 + 5 = 17. MATHEMATICA nxt[{n_, a_}]:={n+1, n+1+Total[Transpose[FactorInteger[a]][[1]]]}; Join[{1}, Transpose[ NestList[nxt, {2, 2}, 70]][[2]]] (* Harvey P. Dale, Mar 11 2015 *) PROG (PARI) b=1; for(i=2, 100, v=factor(b); b=i+sum(j=1, matsize(v)[1], v[j, 1]); print1(b, ", ")) (Klasen) CROSSREFS Sequence in context: A053477 A104956 A020820 * A129140 A002580 A196408 Adjacent sequences: A111287 A111288 A111289 * A111291 A111292 A111293 KEYWORD nonn AUTHOR Leroy Quet, Nov 01 2005 EXTENSIONS More terms from Lambert Klasen (lambert.klasen(AT)gmx.net), Nov 06 2005 STATUS approved

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

Last modified December 9 23:05 EST 2022. Contains 358710 sequences. (Running on oeis4.)