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A321569
Least prime p such that p plus the multiplication of its digits is the n-th prime after p.
3
23, 1163, 233, 163, 29, 283, 293, 443, 5233, 67, 4243, 743, 653, 347, 2239, 439, 1447, 349, 1367, 683, 449, 7451, 3881, 929, 1657, 3257, 15443, 1567, 11587, 7723, 2297, 3259, 4463, 8237, 2377, 3727, 9419, 659, 8951, 2683, 677, 569, 1867, 2467, 3583, 2459, 5743
OFFSET
1,1
LINKS
Carlos Rivera, Puzzle 935. pi+SOD(pi)=p(i+n), The Prime Puzzles and Problems Connection.
EXAMPLE
a(1) = 23 because 23 + 2*3 = 29 that is the first prime after 23.
a(2) = 1163 because 1163 + 1*1*6*3 = 1181 that is the second prime after 1163.
MAPLE
P:=proc(q) local k, n, p; for n from 1 to q do
for k from 1 to q do p:=ithprime(k);
if p+convert(convert(p, base, 10), `*`)=ithprime(k+n) then lprint(n, p);
break; fi; od; od; end: P(10^9);
MATHEMATICA
Array[Block[{p = 2}, While[p + Times @@ IntegerDigits@ p != NextPrime[p, #], p = NextPrime@ p]; p] &, 47] (* Michael De Vlieger, Dec 17 2018 *)
CROSSREFS
KEYWORD
base,nonn,easy
AUTHOR
Paolo P. Lava, Dec 17 2018
STATUS
approved