This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A196527 Greatest common divisor of sums of first n prime numbers and first n composite numbers. 3
 2, 5, 2, 1, 1, 1, 1, 1, 2, 1, 4, 1, 7, 1, 8, 1, 1, 1, 1, 1, 8, 7, 1, 1, 1, 3, 2, 1, 4, 3, 1, 1, 28, 1, 1, 1, 1, 1, 2, 1, 1, 3, 1, 1, 2, 1, 1, 1, 26, 1, 2, 1, 1, 1, 2, 1, 6, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 4, 1, 1, 1, 1, 1, 10, 1, 2, 1, 1, 1, 1, 3, 8 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(n) = gcd(A007504(n),A053767(n)); a(A196528(n)) = n and a(m) <> n for m < A196528(n). LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 EXAMPLE a(1) = gcd(2,4) = 2; a(2) = gcd(2+3,4+6) = gcd(5,10) = 5; a(3) = gcd(2+3+5,4+6+8) = gcd(10,18) = 2; a(4) = gcd(2+3+5+7,4+6+8+9) = gcd(17,19) = 1. MATHEMATICA Module[{nn=90, pr, cmp}, pr=Accumulate[Prime[Range[nn]]]; cmp=Accumulate[ Take[Select[Range[2nn], CompositeQ], nn]]; GCD@@#&/@Thread[{pr, cmp}]] (* Harvey P. Dale, Jul 29 2017 *) CROSSREFS Cf. A196529. Sequence in context: A193083 A146103 A245172 * A064334 A320032 A270061 Adjacent sequences:  A196524 A196525 A196526 * A196528 A196529 A196530 KEYWORD nonn AUTHOR Reinhard Zumkeller, Oct 03 2011 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 March 26 04:32 EDT 2019. Contains 321481 sequences. (Running on oeis4.)