A235680 - OEIS

A235680

The smallest first term of a sequence of n primes such that, after the first, each is equal to the previous prime plus the sum of all of its digits, plus the product of all of its nonzero digits.

%I #20 Aug 11 2015 01:29:11

%S 2,191,163,151,127,1644997,36778597,935715673,50682890749,

%T 16390560362269,63334172492839

%N The smallest first term of a sequence of n primes such that, after the first, each is equal to the previous prime plus the sum of all of its digits, plus the product of all of its nonzero digits.

%C The following term produced in each sequence after the n-th is necessarily a composite integer.

%H C. Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_727.htm">Puzzle 727. Extending the OEIS sequence A235680</a>

%e Example for n=8: a(8)=935715673 because after it the seven primes are 936311069, 936337351, 936490481, 936677149, 938391809, 938811763 and 939029537, with 936311069 = 935715673 + 9*3*5*7*1*5*6*7*3+(9+3+5+7+1+5+6+7+3) and so on...

%Y Cf. A233692, A233783, A090009.

%K nonn,hard,more,base

%O 1,1

%A _Carlos Rivera_, Jan 13 2014

%E a(9) from _Giovanni Resta_, Jan 13 2014

%E a(10)-a(11) from _Giovanni Resta_, Feb 22 2014