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A233794 A bit array representing the primes between 105n-102 and 105n+2 among those numbers in the range relatively prime to 6. 1
32596917119, 19221276355, 32294916984, 27056746064, 13260585324, 19153906256, 11044217692, 10628959443, 23930632312, 27274595010, 12929300524, 9758853778, 21477751664, 18735703058, 6820532604, 1946775235, 27961930040, 10687629457, 28253630548, 10613958227 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

From Riesel: "In a 36-bit computer, the primes in an interval from 105k to 105(k+1) can thus be stored in 35 of the 36 bits of a computer word. This string of bits may be reversed and printed out as an integer <2^35. A prime table up to 105 × 100 = 10500 looks rather strange when printed out in this way (see next page) [this sequence]. The reader should compare this with the prime table up to 12553 provided at the end of this book. The table printed there contains slightly more information than the print-out on the next page, .... On a 3.5 inch magneto-optical  disk, having a storage capacity of 128 Mbytes, there is enough room to store the primes up to about 3,000,000,000 in this way."

a(n) = 0 for almost all n. The first such n is 19151. - Charles R Greathouse IV, Dec 22 2013

REFERENCES

Hans Riesel, Prime Numbers and Computer Methods for Factorization, Second Edition, Birkhäuser, Boston, 1994, pp 8-10.

LINKS

T. D. Noe, Table of n, a(n) for n = 1..10000

MATHEMATICA

Table[t = Select[Range[105*(n - 1) + 3, 105*n + 2], ! IntegerQ[#/2] && ! IntegerQ[#/3] &]; FromDigits[Reverse[Table[If[PrimeQ[i], 1, 0], {i, t}]], 2], {n, 20}] (* T. D. Noe, Dec 30 2013 *)

PROG

(PARI) a(n)=my(s); forstep(n=105*n+2, 105*n-102, -1, if(gcd(n, 6)>1, next); s+=s+isprime(n)); s \\ Charles R Greathouse IV, Dec 22 2013

CROSSREFS

Sequence in context: A017639 A234392 A212942 * A202281 A271818 A034655

Adjacent sequences:  A233791 A233792 A233793 * A233795 A233796 A233797

KEYWORD

nonn,base

AUTHOR

Robert G. Wilson v, Dec 15 2013

STATUS

approved

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Last modified December 14 05:36 EST 2019. Contains 329978 sequences. (Running on oeis4.)