The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A135203 For any integer n >= 1 the sequence gives the minimum power x for which n^x+(n-1)^x+(n-2)^x+...+1^x produces a perfect square. 1
 1, 3, 3, 3, 3, 3, 3, 1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS All 3's apart from 1's in positions given by A001108 and 2 for n=24. LINKS Antti Karttunen, Table of n, a(n) for n = 1..65537 EXAMPLE n=4 -> 4^3+3^3+2^3+1^3 = 64+27+8+1 = 100 n=5 -> 5^3+4^3+3^3+2^3+1^3 = 125+64+27+8+1 = 225 n=6 -> 6^3+5^3+4^3+3^3+2^3+1^3 = 216+125+64+27+8+1 = 441 MAPLE P:=proc(n) local a, i, k, j, ok, x; for i from 1 by 1 to n do x:=1; ok:=1; while ok=1 do a:=0; k:=i; while k>0 do a:=a+k^x; k:=k-1; od; if (trunc(sqrt(a)))^2=a then print(x); ok:=0; else x:=x+1; fi; od; od; end: P(100); PROG (PARI) A135203(n) = for(x=1, oo, if(issquare(sum(k=1, n, k^x)), return(x))); \\ Antti Karttunen, Sep 27 2018 CROSSREFS Cf. A001108. Sequence in context: A251551 A073139 A122845 * A251552 A324497 A179804 Adjacent sequences:  A135200 A135201 A135202 * A135204 A135205 A135206 KEYWORD easy,nonn AUTHOR Paolo P. Lava and Giorgio Balzarotti, Nov 28 2007 EXTENSIONS Offset and a typo in the definition corrected by Antti Karttunen, Sep 27 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 17 02:26 EDT 2021. Contains 343059 sequences. (Running on oeis4.)