A088490 a(n) is the absolute value of p minus A004086(p), where (p-2,p) is the n-th pair of twin primes.

0, 0, 18, 72, 18, 9, 45, 36, 198, 792, 792, 0, 0, 198, 792, 693, 99, 99, 99, 0, 594, 297, 99, 99, 198, 396, 495, 297, 297, 495, 693, 495, 99, 99, 495, 180, 2268, 450, 2538, 2808, 2358, 90, 8442, 630, 1728, 90, 7812, 2088, 2358, 8352, 7452, 360

Offset

1,3

Comments

9 divides each term.

Links

Table of n, a(n) for n=1..52.

Example

The 4th pair of twin primes is (17,19). a(4) then is the absolute value of 19 - 91, which is 72.

Mathematica

a = {}; For[n = 1, n < 275, n++, If[Prime[n + 1] == Prime[n] + 2, AppendTo[a, Abs[Prime[n + 1] - FromDigits[Reverse[IntegerDigits[Prime[n + 1]]]]]]]]; a

Prog

(PARI) revdifftp2(n) = { forprime(x=1, n, if(isprime(x+2), a=vector(x); x1=x+2; z=0; ln=length(Str(x1)); for(y=1, ln, a[y] = x1%10; x1=floor(x1/10); ); for(y=1, ln, z += a[y]*10^(ln-y); ); print1(abs(z-(x+2))" "); ) ) }

Crossrefs

Sequence in context: A135470 A059224 A174492 * A257693 A231328 A274577

Adjacent sequences: A088487 A088488 A088489 * A088491 A088492 A088493

Keyword

base,nonn,less

Author

Cino Hilliard, Nov 09 2003

Extensions

Edited by Stefan Steinerberger, Jul 22 2007

Status

approved