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 A236373 Pseudoprimes to base 2 of the form 6p+1 such that 2^(p-1) == 1 (mod p). 0
 2047, 8388607, 140737488355327, 576460752303423487 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The first four terms are A065341(1), A065341(2), A065341(7), A065341(9) and have the form 2^m-1. Are there terms not of this form? Composite 2^n-1 belong to this sequence when n is in A005385 (e.g., 2^83-1, 2^167-1, etc.) No other terms below 2^64. - Max Alekseyev, May 28 2014 LINKS EXAMPLE 2047=6*341+1; 2^2046 == 1 (mod 2047); 2^340 == 1 (mod 341). CROSSREFS Subsequence of A001567. Sequence in context: A131952 A065341 A135976 * A289476 A222526 A035892 Adjacent sequences:  A236370 A236371 A236372 * A236374 A236375 A236376 KEYWORD nonn,more AUTHOR Alzhekeyev Ascar M, Jan 24 2014 EXTENSIONS a(4) from Max Alekseyev, May 28 2014 STATUS approved

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Last modified August 8 02:45 EDT 2020. Contains 336290 sequences. (Running on oeis4.)