This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A241603 a(n) = Sum_{d|n, d <= 5} d^2 + 5*Sum_{d|n, d>5} d. 2
 1, 5, 10, 21, 26, 44, 36, 61, 55, 80, 56, 120, 66, 110, 110, 141, 86, 179, 96, 196, 150, 170, 116, 280, 151, 200, 190, 266, 146, 344, 156, 301, 230, 260, 236, 435, 186, 290, 270, 436, 206, 464, 216, 406, 380, 350, 236, 600, 281, 455, 350, 476, 266, 584, 356, 586, 390, 440, 296, 820, 306, 470, 510, 621, 416, 704, 336 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 REFERENCES P. A. MacMahon, The connexion between the sum of the squares of the divisors and the number of partitions of a given number, Messenger Math., 54 (1924), 113-116. Collected Papers, MIT Press, 1978, Vol. I, pp. 1364-1367. LINKS Harvey P. Dale, Table of n, a(n) for n = 1..1000 MAPLE with(numtheory): A:=proc(s, n) local d, s1, s2; s1:=0; s2:=0; for d in divisors(n) do if d <= s then s1:=s1+d^2 else s2:=s2+d; fi; od: s1+s*s2; end; f:=s->[seq(A(s, n), n=1..80)]; f(5); MATHEMATICA sd5[n_]:=Module[{d=Divisors[n]}, Total[Select[d, #<6&]^2]+5Total[Select[ d, #>5&]]]; Array[sd5, 70] (* Harvey P. Dale, Mar 18 2015 *) CROSSREFS Cf. A002659, A002660. A row of the array in A242639. Sequence in context: A002791 A080399 A017667 * A242643 A276959 A001157 Adjacent sequences:  A241600 A241601 A241602 * A241604 A241605 A241606 KEYWORD nonn AUTHOR N. J. A. Sloane, May 21 2014 EXTENSIONS Typo in definition corrected by N. J. A. Sloane, Mar 18 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.

Last modified October 18 17:13 EDT 2019. Contains 328186 sequences. (Running on oeis4.)