A068396 n-th prime minus its reversal.

0, 0, 0, 0, 0, -18, -54, -72, -9, -63, 18, -36, 27, 9, -27, 18, -36, 45, -9, 54, 36, -18, 45, -9, 18, 0, -198, -594, -792, -198, -594, 0, -594, -792, -792, 0, -594, -198, -594, -198, -792, 0, 0, -198, -594, -792, 99, -99, -495

Offset: 1

Author

Reinhard Zumkeller, Mar 08 2002

Keywords

• sign
• base
• nice
• look

Comments

a(n) = 0 for n in A075807. - Michel Marcus, Sep 27 2017

All terms are divisible by 9. - Zak Seidov, Jun 05 2021

Examples

			a(10) = 29 - 92 = -63;
a(20) = 71 - 17 = 54.
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000040, A004086, A056965, A061227, A075807.

Programs

Haskell

a068396 n = p - a004086 p  where p = a000040 n
-- Reinhard Zumkeller, Feb 04 2014

Mathematica

#-IntegerReverse[#]& /@ Prime[Range[50]] (* Harvey P. Dale, Dec 20 2012 *)

PARI

a(n) = prime(n) - fromdigits(Vecrev(digits(prime(n)))); \\ Michel Marcus, Sep 27 2017

Python

from sympy import prime
def a(n): pn = prime(n); return pn - int(str(pn)[::-1])
print([a(n) for n in range(1, 50)]) # Michael S. Branicky, Jun 05 2021

Formula

a(n) = A000040(n) - A004087(n).

a(n) = A056965(A000040(n)). - Michel Marcus, Sep 27 2017