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 A076107 First of n consecutive integers whose sum is a positive n-th power, or 0 if no such integers exist. 3
 1, 0, 8, 0, 623, 119, 117646, 0, 2183, 976558, 25937424596, 0, 23298085122475, 48444505197, 29192926025390618, 0, 48661191875666868473, 21523352, 104127350297911241532832, 0, 278218429446951548637196391 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS No sum exists precisely when n == 0 (mod 4). a(2) = 0 is a legitimate value. The sum is given by A076108(n) = A076109(n)^n for n != 0 (mod 4). a(p) = p^(p-1)-(p-1)/2 for prime p. LINKS FORMULA a(n) = A076108(n)/n-(n-1)/2 for n != 0 (mod 4). a(4k)=0; otherwise a(n) = (2*A076108(n)/n - n + 1)/2 = (2*p1^n*...*pm^n/n - n + 1)/2 where p1, ..., pm are all distinct odd primes dividing n. - Max Alekseyev, Jun 10 2005 EXAMPLE a(3) = 8 as 8+9+10 = 27 = 3^3. a(6) = 119 as 119+120+..+124 = 729 = 3^6. PROG (PARI) for(n=1, 30, t=n*(n-1)/2:f=0:for(r=1, 10^4, if((r^n-t)%n==0, f=(r^n-t)/n:break)):print1(f", ")) (PARI) {A076107(n)=if(n%4==0, return(0)); m=n; if(m%2==0, m\=2); f=factorint(m)[, 1]; p=1; (2*prod(i=1, length(f), f[i])^n/n-n+1)/2} (Alekseyev) CROSSREFS Cf. A076108, A076109. Sequence in context: A221421 A013456 A180738 * A076952 A209914 A342980 Adjacent sequences:  A076104 A076105 A076106 * A076108 A076109 A076110 KEYWORD nonn AUTHOR Amarnath Murthy, Oct 08 2002 EXTENSIONS Corrected and extended by Ralf Stephan, Mar 30 2003 Revised by Max Alekseyev and David W. Wilson, Jun 10 2005 More terms from Max Alekseyev, Jun 10 2005 STATUS approved

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Last modified December 5 15:06 EST 2021. Contains 349557 sequences. (Running on oeis4.)