login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

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.
1
8, 243, 128, 216, 12167, 1906624, 6859, 226981, 3125, 12167, 1252726552, 325660672, 1331, 19902511000, 32768, 537824, 69934528000, 704969, 39304, 42875, 50653, 751089429, 79507, 314432, 21952, 22665187, 47437928, 1605723211, 10648, 287496, 5177717, 7414875
OFFSET
1,1
COMMENTS
Having sequences with limits (10^7) is not OEIS policy. We make an exception here. - T. D. Noe, Jul 11 2013
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)
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.
EXAMPLE
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).
PROG
(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, ", "))))
CROSSREFS
Sequence in context: A351370 A272236 A272239 * A229544 A115613 A209540
KEYWORD
nonn,less
AUTHOR
Robin Garcia, Jul 06 2013
STATUS
approved