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%I #23 Feb 24 2024 01:08:04
%S 2,11,11,277,37783,516493,286330897,286330897,56676324799
%N Begins the earliest length-n chain of primes such that any term in the chain equals the previous term increased by the sum of its digits.
%C From the second term on, subsequence of A[2] := A048519. Due to the "exclusive" definition of this sequence, A048523(1) > a(2), but for k >= 3, a(k) = A[k](1) for A[3..9] = A048524 .. A048527, A320878 .. A320880. - _M. F. Hasler_, Nov 09 2018
%H Carlos Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_163.htm">Puzzle 163. P+SOD(P)</a>
%e 11 begins the earliest chain 11, 13, 17 of three primes such that any term in the chain equals the previous term increased by the sum of its digits, viz., 13 = 11 + 2, 17 = 13 + 4. Hence a(3) = 11.
%o (PARI) A090009(n,P=2)=forprime(p=P,,P=p;for(i=2,n,isprime(P=A062028(P))||next(2));return(p))
%o P=0; A090009_vec=vector(6,n,P=A090009(n,P)) \\ Takes long for n > 6. - _M. F. Hasler_, Nov 09 2018
%Y Cf. A047791, A048519, A062028 (n + digit sum of n).
%Y Cf. A048523 .. A048527, A320878 .. A320880.
%K base,more,nonn
%O 1,1
%A _Joseph L. Pe_, Jan 27 2004
%E a(7)-a(8) from _Donovan Johnson_, Jan 08 2013
%E a(9) from _Giovanni Resta_, Jan 14 2013
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