This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A305676 a(n) = A305671(A305672(n)). 6
 7, 24, 72, 144, 240, 336, 504, 720, 576, 720, 1440, 2016, 2880, 4320, 5760, 10080, 10080, 10080, 10080, 8640, 8640, 10080, 17280, 15120, 17280, 17280, 17280, 20160, 30240, 40320, 60480, 120960, 181440, 241920, 362880, 483840, 725760, 1451520, 2177280, 2419200, 2419200 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Do any numbers x exist that never occur in this sequence? Can this be proven for any particular value of x? For example, does 96 occur in this sequence? Note that 96 occurs four times as a value of sigma among the initial 100 composites. LINKS PROG (PARI) composite(n) = my(i=0); forcomposite(c=1, , i++; if(i==n, return(c))) mcv(v) = my(w=vecsort(v, , 8), count=vector(#w), ind=0, i=0); for(x=1, #w, for(y=1, #v, if(w[x]==v[y], count[x]++))); for(k=1, #count, if(count[k]==vecmax(count), ind=k; i++)); if(i > 1, return(0), return(w[ind])) a305671(n) = my(v=[]); for(k=1, n, v=concat(v, sigma(composite(k)))); mcv(v) terms(n) = my(x=0, k=1, i=0); while(1, if(a305671(k) > 0, print1(a305671(k), ", "); i++); if(i==n, break); while(a305671(k) > 0, k++); while(a305671(k)==0, k++)) terms(11) \\ Print initial 11 terms of the sequence CROSSREFS Cf. A145899, A305671, A305672, A305673, A305675, A305676. Sequence in context: A211382 A217746 A211381 * A101903 A212504 A196349 Adjacent sequences:  A305673 A305674 A305675 * A305677 A305678 A305679 KEYWORD nonn AUTHOR Felix FrÃ¶hlich, Jun 08 2018 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 April 22 14:25 EDT 2019. Contains 322349 sequences. (Running on oeis4.)