The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A067316 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A067316

a(n) is the number of values of j, 0 <= j <= n, such that 1 + binomial(n,j) is prime.
(history; published version)

#17 by OEIS Server at Thu Jul 18 09:18:35 EDT 2024

LINKS

Amiram Eldar, <a href="/A067316/b067316_1.txt">Table of n, a(n) for n = 0..10000</a>

#16 by Michael De Vlieger at Thu Jul 18 09:18:35 EDT 2024

STATUS

reviewed

approved

Discussion

Thu Jul 18

09:18

OEIS Server: Installed first b-file as b067316.txt.

#15 by Joerg Arndt at Thu Jul 18 01:57:54 EDT 2024

STATUS

proposed

reviewed

#14 by Amiram Eldar at Thu Jul 18 01:54:14 EDT 2024

STATUS

editing

proposed

#13 by Amiram Eldar at Thu Jul 18 01:25:53 EDT 2024

EXAMPLE

For n = 8, the primes are 2, 29, 71, 29, 2, so a(n) = 5.

a(n) = 6 for n = 9, 10, 11, 12. Also, a(n) = 10 for n = 149, ..., 154.

#12 by Amiram Eldar at Thu Jul 18 01:24:52 EDT 2024

PROG

(PARI) a(n) = 2 * sum(k=0, (n-1)\2, isprime(binomial(n, k) + 1)) + if(!(n%2), isprime(binomial(n, n/2) + 1)); \\ Amiram Eldar, Jul 18 2024

CROSSREFS

Cf. A066699, A067317.

#11 by Amiram Eldar at Thu Jul 18 01:24:00 EDT 2024

LINKS

Amiram Eldar, <a href="/A067316/b067316_1.txt">Table of n, a(n) for n = 0..10000</a>

STATUS

approved

editing

#10 by Bruno Berselli at Tue Oct 30 03:34:20 EDT 2018

STATUS

proposed

approved

#9 by Michel Marcus at Tue Oct 30 03:06:24 EDT 2018

STATUS

editing

proposed

#8 by Michel Marcus at Tue Oct 30 03:06:21 EDT 2018

EXAMPLE

For n=8, the primes are 2,29,71,29,2, so a(n)=5. a(n)=6 for n=9,10,11,12. Also, a(n)=10 for n=149,...,154.

a(n)=6 for n=9,10,11,12. Also, a(n)=10 for n=149,...,154.

PROG

(PARI) a(n) = sum(j=0, n, isprime(1 + binomial(n, j))); \\ Michel Marcus, Oct 30 2018

STATUS

proposed

editing