cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A227319 Powers but not squares which are sum of consecutive primes less than 10^7 ordered according to the proximity of the first prime of the sum to the first prime: 2.

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%I A227319 #10 Apr 26 2025 20:11:43
%S A227319 8,243,128,216,12167,1906624,6859,226981,3125,12167,1252726552,
%T A227319 325660672,1331,19902511000,32768,537824,69934528000,704969,39304,
%U A227319 42875,50653,751089429,79507,314432,21952,22665187,47437928,1605723211,10648,287496,5177717,7414875
%N A227319 Powers but not squares which are sum of consecutive primes less than 10^7 ordered according to the proximity of the first prime of the sum to the first prime: 2.
%C A227319 Having sequences with limits (10^7) is not OEIS policy. We make an exception here. - _T. D. Noe_, Jul 11 2013
%C A227319 There are 3 other important informative parameters (A 4-dimensional sequence from an informative point of view) for each term of the sequence : (b,l,k) where b is the base powered, l is the number of primes added and k is the k-th prime where the sum of the consecutive primes begin : (2,2,2), (3,5,13), (2,2,18), (6,2,28), (23,47,32), (124,704,34), (19,25,46), (61,233,47), (5,11,55), (23,27,74), (1078,15442,74), (688,8116,78), (11,3,85), (2710,57856,87), (2,48,99), (14,320,100), (4120,105616,111), (89,345,135), (34,42,139), (35,45,140), (37,51,143), (909,12023,149), (43,65,168), (68,186,170), (28,20,174), (283,2137,205), (362,3102,206), (1171,17211,247), (22,6,273), (66,126,277), (173,907,292), (195,1107,303)
%C A227319 The limit (of 10^7) in the name/definition of the sequence is necessary because no power with exponent greater than 2 has been found for sums of primes beginning with first prime. Or beginning with many other primes. Naturally this limit could be much widened and alter the sequence; but this is why I put it in the name.
%e A227319 8 = 2^3 = 3 + 5; 243 = 3^5 = 41 + 43 + 47 + 53 + 59; 128 = 2^7 = 61 + 67; 216 = 6^3 = 107 + 109; 12167 = 23^3 = S(47,32) = Sum of 47 primes beginning with p(32); ... ; 11^3 = 1331 = 439 + 443 + 449; 5^5 = 3125 = S(11,55); 11^5 = 161051 = S(47,458); 2^13 = 8192 = 4093 + 4099;  3^13 = 1594323 = S(233,764); 2^17 = 131072 = S(40,443) = S(8,1896); 7^7 = 823543 = S(7^2,1917); 2^25 = S(1268,2269); 2001^3 = S(35209,2368).
%o A227319 (PARI) n=10^7;v=vector(n);i=0;for(a=2,n,if(isprime(a),i++;v[i]=a));for(b=1,315,k=0;for(j=b,i,k=k+v[j];if(ispower(k,,&n)&!issquare(k),print1(k,", "))))
%Y A227319 Cf. A141092, A227249.
%K A227319 nonn,less
%O A227319 1,1
%A A227319 _Robin Garcia_, Jul 06 2013