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A118572 Sophie Germain primes for which the product of the digits is square. 1
11, 41, 191, 281, 419, 491, 509, 683, 809, 911, 1013, 1019, 1031, 1049, 1103, 1229, 1289, 1409, 1499, 1559, 1601, 1889, 1901, 2003, 2039, 2063, 2069, 2129, 2693, 2819, 2903, 2963, 3023, 3413, 3803, 4019, 4073, 4409, 4919, 5003, 5039, 5051, 5081, 5303 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

1499 is in the sequence because (1) it is a Sophie Germain prime and (2) the product of its digits 1*4*9*9=324, which is a square.

MATHEMATICA

Select[Prime[Range[1000]], PrimeQ[2#+1]&&IntegerQ[Sqrt[Times@@ IntegerDigits[ #]]]&] (* Harvey P. Dale, Dec 29 2014 *)

CROSSREFS

Cf. A005384.

Sequence in context: A156733 A079304 A260270 * A201709 A092445 A068840

Adjacent sequences:  A118569 A118570 A118571 * A118573 A118574 A118575

KEYWORD

base,nonn

AUTHOR

Luc Stevens (lms022(AT)yahoo.com), May 07 2006

STATUS

approved

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Last modified December 13 17:13 EST 2019. Contains 329970 sequences. (Running on oeis4.)