login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A335907 Average of those twin prime pairs p, q=p+2, for which A335885(p+1) <= A335885(p-1) and A335885(q-1) <= A335885(q+1). 2
4, 12, 72, 102, 108, 180, 192, 240, 348, 420, 600, 822, 828, 1032, 1050, 1152, 1302, 1320, 1428, 1488, 1608, 1722, 1872, 2088, 2112, 2550, 2592, 2688, 2712, 3000, 3168, 3252, 3360, 3372, 3468, 3528, 3672, 3768, 4020, 4092, 4128, 4272, 4650, 4800, 4932, 5100, 5232, 5280, 5520, 5640, 5868, 5880, 6132, 6690, 6762, 6780 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

For such twin prime pairs p, q, A335885(p) = A335885(q) = 1 + A335885((p+q)/2).

LINKS

Table of n, a(n) for n=1..56.

PROG

(PARI)

A335885(n) = { my(f=factor(n)); sum(k=1, #f~, if(2==f[k, 1], 0, f[k, 2]*(1+min(A335885(f[k, 1]-1), A335885(f[k, 1]+1))))); };

isA335907(n) = (isprime(n-1)&&isprime(n+1)&&(A335885(n)<=A335885(n-2))&&(A335885(n)<=A335885(n+2)));

CROSSREFS

Cf. A335885.

Subsequence of A014574. Cf. also A335908.

Sequence in context: A302434 A121771 A009621 * A013195 A323295 A166746

Adjacent sequences:  A335904 A335905 A335906 * A335908 A335909 A335910

KEYWORD

nonn

AUTHOR

Antti Karttunen, Jul 01 2020

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 15 10:22 EDT 2021. Contains 342977 sequences. (Running on oeis4.)