A335908 Average of those twin prime pairs p, q=p+2, for which A335884(p+1) >= A335884(p-1) and A335884(q-1) >= A335884(q+1).

6, 18, 30, 42, 102, 138, 150, 198, 270, 282, 462, 522, 570, 618, 642, 810, 822, 858, 882, 1050, 1062, 1230, 1278, 1290, 1302, 1482, 1698, 1722, 1878, 1950, 1998, 2082, 2130, 2142, 2238, 2310, 2382, 2550, 2658, 2730, 2790, 2802, 2970, 3258, 3300, 3330, 3390, 3462, 3558, 3582, 3822, 3918, 3930, 4002, 4050, 4158, 4218, 4230, 4242

Offset

1,1

Comments

For such twin prime pairs p, q, A335884(p) = A335884(q) = 1 + A335884((p+q)/2).

Links

Table of n, a(n) for n=1..59.

Prog

(PARI)
A335884(n) = { my(f=factor(n)); sum(k=1, #f~, if(2==f[k, 1], 0, f[k, 2]*(1+max(A335884(f[k, 1]-1), A335884(f[k, 1]+1))))); };
isA335908(n) = (isprime(n-1)&&isprime(n+1)&&(A335884(n)>=A335884(n-2))&&(A335884(n)>=A335884(n+2)));

Crossrefs

Cf. A335884.

Subsequence of A014574. Cf. also A335907.

Sequence in context: A242394 A030568 A017593 * A096286 A256256 A344596

Adjacent sequences: A335905 A335906 A335907 * A335909 A335910 A335911

Keyword

nonn

Author

Antti Karttunen, Jul 01 2020

Status

approved