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 A227249 Number of consecutive composites beginning with the first, to be added to obtain a power. 2
 1, 4, 6, 21, 80, 4151, 6982, 269563, 779693, 834365, 16176645, 19770092, 41049539, 228612936, 1950787140, 2404785364, 3095996836, 5236785750 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS All powers are squares with the exception of 3^3 for a(2) and 6^9 for a(6). I conjecture these are the only nonsquare powers. a(19) > 10^10. - Zak Seidov, Jul 06 2013 LINKS FORMULA {n: A053767(n) in A001597}. -  Zak Seidov, Jul 06 2013 EXAMPLE Considering 1 not to be prime and not to be composite, first composite is 4 which is 2^2. And the sum of the first four composites is 4 + 6 + 8 + 9 = 27 = 3^3. MAPLE # see A001597 for isA001597 for n from 1 do     if isA001597(A053767(n) ) then         print(n) ;     end if; end do: # R. J. Mathar, Jul 08 2013 PROG (PARI) : n=10^7; v=vector(n); i=0; for(a=2, n, if(isprime(a), next, i++; v[i]=a)); k=0; for(j=1, i, k=k+v[j]; if(ispower(k, , &n), print1([k, n, j], " "))) CROSSREFS Cf. A001597, A002808, A053767, A141092. Sequence in context: A229743 A151520 A282517 * A002270 A286358 A088228 Adjacent sequences:  A227246 A227247 A227248 * A227250 A227251 A227252 KEYWORD nonn,more AUTHOR Robin Garcia, Jul 04 2013 EXTENSIONS a(11) - a(18) from Zak Seidov, Jul 06 2013 STATUS approved

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Last modified September 17 22:53 EDT 2019. Contains 327147 sequences. (Running on oeis4.)