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.

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A350830 Number of prime 10-tuples (or decaplets) with initial member (A257127) between 10^(n-1) and 10^n.

Original entry on oeis.org

0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 4, 15, 81, 357, 1685, 8256
Offset: 1

Views

Author

M. F. Hasler, Mar 01 2022

Keywords

Comments

"Between 10^(n-1) and 10^n" is equivalent to saying "with n (decimal) digits".
A prime 10-tuple (or decaplet) is a sequence of 9 consecutive primes (p1, ..., p10) of minimum possible diameter p10 - p1 = 32.
Terms a(1)-a(16) computed from b-files a(1..10^4) for A027569 and A027570. Using Luhn's data (cf. LINKS) one can obtain a(18) and a(19).
So far the last term of all the decaplets has the same number of digits as the initial term.

Examples

			a(2) = 1 because 11 is the only two-digit prime to start a prime decaplet, i.e., member of A257127.
a(n) = 0 for all other n < 10 because the next larger prime decaplet is made of 10-digit primes, A257127(2) = 9853497737 and successors.
a(10) = 1 because there is only one prime decaplet made of 10-digit primes.
a(11) = 4 because there are only four terms in A257127 (for indices n = 3..6) which have 11 digits.
		

Crossrefs

Cf. A257127 (initial members p of prime 9-tuples (p, ..., p+32)), A027569, A027570 (idem, specifically for each of the two possible patterns).
Cf. A350825 - A350829: similar for quintuples, sextuples, septuples, octuples and 9-tuples.

Programs

  • PARI
    (D(v)=v[^1]-v[^-1])( [setsearch(A257127,10^n,1) | n<-[0..16]] ) \\ where A257127 is a vector of at least 10400 terms of that sequence.
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