The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A104426 Numbers k such that the digit 6 does not appear in the decimal expansion of k, Pk, Pk+k, Pk-k, or Pk*k, where Pk is the k-th prime. 1
 1, 3, 4, 7, 8, 9, 10, 11, 12, 13, 20, 21, 22, 25, 30, 33, 35, 37, 41, 43, 44, 48, 50, 51, 52, 53, 54, 55, 58, 70, 72, 75, 80, 81, 82, 83, 85, 93, 95, 128, 149, 152, 170, 171, 174, 184, 185, 187, 188, 189, 194, 198, 201, 203, 210, 212, 215, 217, 233, 235, 238, 242, 245 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS From the first 3000 primes, only 179 are terms. From the first 3000 integers, only 343 are terms. LINKS MATHEMATICA id[x_]:=IntegerDigits[x]; pr[i_]:=Prime[i]; ra=Range[3000]; A104426=Select[ra, Position[Union[id[ # ], id[pr[ # ]], id[pr[ # ]+# ], id[pr[ # ]-# ], id[pr[ # ]*# ]], 6]=={}&] slQ[n_]:=Module[{p=Prime[n]}, Union[DigitCount[#, 10, 6]&/@{n, p, p+n, p-n, p*n}] == {0}]; Select[Range[250], slQ] (* Harvey P. Dale, Feb 01 2018 *) PROG (PARI) has(n)=!setsearch(Set(digits(n)), 6) is(n, p=prime(n))=has(n) && has(p) && has(p+n) && has(p-n) && has(p*n) \\ Charles R Greathouse IV, Feb 01 2018 CROSSREFS Cf. A052414, A104419, A104420, A104421, A104422, A104423, A104424, A104425, A104427, A104428. Sequence in context: A213622 A246847 A193406 * A097044 A198330 A232779 Adjacent sequences:  A104423 A104424 A104425 * A104427 A104428 A104429 KEYWORD nonn,base AUTHOR Zak Seidov, Mar 07 2005 EXTENSIONS Definition modified (at the suggestion of N. J. A. Sloane) by Harvey P. Dale, Feb 10 2018 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified April 9 06:59 EDT 2020. Contains 333344 sequences. (Running on oeis4.)