This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A068395 #22 Aug 26 2015 01:51:04 %S A068395 0,0,0,0,9,9,9,9,18,18,27,27,36,36,36,45,45,54,54,63,63,63,72,72,81, %T A068395 99,99,99,99,108,117,126,126,126,135,144,144,153,153,162,162,171,180, %U A068395 180,180,180,207,216,216,216,225,225,234,243,243,252,252,261,261,270 %N A068395 a(n) = n-th prime minus its sum of digits. %C A068395 a(i) <= a(j) for i < j. %C A068395 A number and the sum of its digits have the same value modulo 9. Hence all terms are divisible by 9. - _Stefan Steinerberger_, Apr 01 2006 %C A068395 A192977 gives number of occurrences of multiples of 9. - _Reinhard Zumkeller_, Aug 04 2011 %C A068395 Margaret Coffey (ed.) p. 440: "The sum of the digits of a two-digit prime number is subtracted from the number. Prove that the difference cannot be a prime number." Proof [p.442] "Let a and b be the tens and units digits, respectively, and let 10a+b be the prime. Subtract the sum of the digits from the number: 10a + b - (a+b) = 9a. The difference is a multiple of 9 and cannot, therefore, be prime." - _Jonathan Vos Post_, Feb 02 2012 %H A068395 Reinhard Zumkeller, <a href="/A068395/b068395.txt">Table of n, a(n) for n = 1..10000</a> %H A068395 Margaret Coffey, Editor, <a href="http://www.jstor.org/stable/10.5951/mathteacher.105.6.0440">Problem #3, Calendar</a>, Mathematics Teacher, March 2012, pp. 440-442. %F A068395 a(n) = A000040(n) - A007953(A000040(n)). %e A068395 a(10) = 29 - (2+9) = 18. %t A068395 Table[Prime[n] - Sum[DigitCount[Prime[n]][[i]]*i, {i, 1, 9}], {n, 1, 60}] (* _Stefan Steinerberger_, Apr 01 2006 *) %t A068395 #-Total[IntegerDigits[#]]&/@Prime[Range[60]] (* _Harvey P. Dale_, Oct 14 2014 *) %o A068395 (Haskell) %o A068395 a068395 n = a068395_list !! (n-1) %o A068395 a068395_list = zipWith (-) a000040_list a007605_list %o A068395 -- _Reinhard Zumkeller_, Aug 04 2011 %Y A068395 Cf. A065073. %K A068395 nonn,nice,base %O A068395 1,5 %A A068395 _Reinhard Zumkeller_, Mar 08 2002 %E A068395 More terms from _Stefan Steinerberger_, Apr 01 2006