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A228575 Pseudoprimes n to base 2 such that n-4, n-2 and n+2 are primes. 4
645, 656601, 6212361, 18958567881, 287468425245, 626160901281, 1395494019921, 1925525109201, 1960708164801, 1962378065901, 1977370759365, 2788325761551, 3032013857181, 6877227801081, 22298617759881, 30242009317521, 39454593651201, 42401101442001 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All numbers in this sequence end in either 5 or 1.

LINKS

Shyam Sunder Gupta, Table of n, a(n) for n = 1..831

EXAMPLE

645 is a pseudoprime (base 2) and 641, 643 and 647 are primes.

CROSSREFS

Cf. A001567, A057942, A230488, A230489.

Sequence in context: A067845 A057942 A230488 * A250989 A187434 A046020

Adjacent sequences:  A228572 A228573 A228574 * A228576 A228577 A228578

KEYWORD

nonn

AUTHOR

Shyam Sunder Gupta, Oct 27 2013

STATUS

approved

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Last modified March 7 10:30 EST 2021. Contains 341869 sequences. (Running on oeis4.)