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A320880
Primes such that iteration of A062028 (n + its digit sum) yields 8 primes in a row.
7
56676324799, 373169411809, 2121959132809, 10180781225809, 14328311692789, 17429111275789, 32594135422789, 34327062247789, 39262151325799, 57404320087789, 60760513291789, 63116080460809, 66105224572789, 92054642332789, 98606700040789
OFFSET
1,1
COMMENTS
Term a(1) is immediate to find from the nearly equal terms A320879(7..8); terms a(2..9) were found by G. Resta as answer to Rivera's Puzzle 163, cf. link.
FORMULA
A320880 = { n in A320879 | A062028(n) in A320879 }.
PROG
(PARI) is_A320880(n)=isprime(n=A062028(n))&& is_A320879(n)
CROSSREFS
Cf. A047791, A048519, A062028 (n + digit sum of n).
Subsequence of A320879 which is subsequence of A320878.
a(1) = A090009(9) = start of first chain of 9 primes under iteration of A062028.
Sequence in context: A344196 A346365 A295042 * A015401 A273930 A273931
KEYWORD
nonn,base
AUTHOR
Zak Seidov and M. F. Hasler, Nov 08 2018
EXTENSIONS
a(10)-a(15) from Lars Blomberg, Feb 10 2019
STATUS
approved