![]() |
Near-repdigit |
To get a more general form, two things have been tried:
>rank prime digits who when comment 1 993 · 101768283 - 1 1768286 L4879 Feb 2019 Near - repdigit 2 9 · 101762063 - 1 1762064 L4879 Aug 2020 Near - repdigit 3 8 · 101715905 - 1 1715906 L4879 Aug 2020 Near - repdigit 4 9992 · 101567410 - 1 1567414 L4879 Aug 2020 Near - repdigit 5 99 · 101536527 - 1 1536529 L4879 Feb 2019 Near - repdigit 6 992 · 101533933 - 1 1533936 L4879 Feb 2019 Near - repdigit 7 92 · 101439761 - 1 1439763 L4789 Dec 2020 Near - repdigit 8 2 · 101059002 - 1 1059003 L3432 Sep 2013 Near - repdigit 9 93 · 101029523 - 1 1029525 L4789 Jan 2019 Near - repdigit 10 9 · 101009567 - 1 1009568 L3735 Sep 2016 Near - repdigit 11 96 · 10846519 - 1 846521 L2425 Sep 2011 Near - repdigit 12 92 · 10833852 - 1 833854 L4789 Apr 2018 Near - repdigit 13 93 · 10642225 - 1 642227 L4789 Mar 2020 Near - repdigit 14 8 · 10608989 - 1 608990 p297 May 2011 Near - repdigit 15 92 · 10544905 - 1 544907 L3735 May 2015 Near - repdigit 16 5 · 10511056 - 1 511057 p297 Mar 2011 Near - repdigit 17 95 · 10466002 - 1 466004 L3735 May 2014 Near - repdigit 18 5 · 10464843 - 1 464844 p297 Feb 2011 Near - repdigit 19 5 · 10445773 - 1 445774 p297 Jan 2011 Near - repdigit 20 999999998 · 10419343 - 1 419352 L1958 Apr 2019 Near - repdigit
- Caldwell89
- C. Caldwell, "The near repdigit primes 333 ... 331," J. Recreational Math., 21:4 (1989) 299--304.
- Caldwell90
- C. Caldwell, "The near repdigit primes AnB, ABn, and UBASIC," J. Recreational Math., 22:2 (1990) 100--109.
- CD95
- C. Caldwell and H. Dubner, "The near repunit primes 1n-k-1011k," J. Recreational Math., 27 (1995) 35--41.
- CD97
- C. Caldwell and H. Dubner, "The near repdigit primes An-k-1B1Ak, especially 9n-k-1819k," J. Recreational Math., 28:1 (1996-97) 1--9.
- Heleen98
- Heleen, J. P., "More near-repunit primes 1n-k-1D11k, D=2,3, ..., 9," J. Recreational Math., 29:3 (1998) 190--195.
- Williams78b
- H. C. Williams, "Some primes with interesting digit patterns," Math. Comp., 32 (1978) 1306--1310. Corrigendum in 39 (1982), 759. MR 58:484