A192545 Numbers such that all numbers are composite when replacing exactly one digit with another, except the leading digit with zero.

200, 202, 204, 205, 206, 208, 320, 322, 324, 325, 326, 328, 510, 512, 514, 515, 516, 518, 530, 532, 534, 535, 536, 538, 620, 622, 624, 625, 626, 628, 840, 842, 844, 845, 846, 848, 890, 892, 894, 895, 896, 898, 1070, 1072, 1074, 1075, 1076, 1078, 1130, 1132

Offset

1,1

Comments

A048853(a(n)) = 0;

Intersection of this sequence and A000040 is A158124. - Evgeny Kapun, Dec 13 2016

If the last digit of an element is 0, 2, 4, 5, 6 or 8, then replacing it with 0, 2, 4, 5, 6 or 8 also yields an element. - David A. Corneth and corrected by Evgeny Kapun, Dec 13 2016

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Mathematica

Select[Range@ 1200, Function[w, Total@ Boole@ Flatten@ Map[Function[d, PrimeQ@ FromDigits@ ReplacePart[w, d -> #] & /@ If[d == 1, #, Prepend[#, 0]] &@ Range@ 9], Range@ Length@ w] == 0]@ IntegerDigits@ # &] (* Michael De Vlieger, Dec 13 2016 *)

Prog

(Haskell)
import Data.List (elemIndices)
a192545 n = a192545_list !! (n-1)
a192545_list = map (+ 1) $ elemIndices 0 $ map a048853 [1..]

Crossrefs

Subsequences: A050249, A118118, A143641, A158124, A158125.

Sequence in context: A239525 A180104 A114984 * A118118 A124472 A247399

Adjacent sequences: A192542 A192543 A192544 * A192546 A192547 A192548

Keyword

nonn,base

Author

Reinhard Zumkeller, Jul 05 2011

Status

approved