This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A266955 Intersection of A046346 (numbers that are divisible by the sum of their prime factors, counted with multiplicity) and A097889 (numbers that are products of at least two consecutive primes). 1
 30, 105, 15015, 9699690, 37182145, 215656441, 955049953, 33426748355, 247357937827, 1448810778701, 3710369067405, 304250263527210, 102481630431415235, 1086305282573001491, 261682369333342226303, 37420578814667938361329, 241532826894674874877669 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Alladi and Erdős ask if this sequence is infinite and give 3 terms: 2*3*5, 2*3*5*7*11*13*17*19 and 2*3*5*7*11*13*17*19*23*29*31*37*41, that is, a(1), a(4) and a(12). This sequence contains A159578(n) for all values of n > 1. - Altug Alkan, Jan 07 2016 LINKS Hiroaki Yamanouchi, Table of n, a(n) for n = 1..500 K. Alladi and P. Erdős, On an additive arithmetic function, Pacific J. Math., Volume 71, Number 2 (1977), 275-294. PROG (PARI) sopfr(n) = {my(f=factor(n)); sum(k=1, #f~, f[k, 1]*f[k, 2]); } list(lim)= {my(v=List(), p, t); for(e=2, log(lim+.5)\log(2), p=1; t=prod(i=1, e-1, prime(i)); forprime(q=prime(e), lim, t*=q/p; if(t>lim, next(2)); if (! (t % sopfr(t)), listput(v, t)); p=nextprime(p+1))); vecsort(Vec(v)); } \\ adapted from A097889 CROSSREFS Cf. A046346, A097889, A159578. Sequence in context: A158445 A046301 A193873 * A205836 A043466 A044281 Adjacent sequences:  A266952 A266953 A266954 * A266956 A266957 A266958 KEYWORD nonn AUTHOR Michel Marcus, Jan 07 2016 EXTENSIONS a(13)-a(17) from Hiroaki Yamanouchi, Jan 12 2016 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.

Last modified September 19 11:26 EDT 2019. Contains 327193 sequences. (Running on oeis4.)