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!)
 A111350 Squares n such that 2*n + 1 is a semiprime. 2
 4, 16, 25, 64, 100, 144, 169, 196, 225, 289, 324, 361, 529, 784, 961, 1024, 1521, 1936, 2304, 2401, 2500, 2809, 2916, 3025, 3249, 3364, 3600, 3969, 4096, 4624, 4761, 5041, 5776, 6084, 6561, 6724, 7056, 7225, 7396, 7921, 8100, 8281, 10816, 11664, 12321 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS FORMULA a(n) = (A111351(n)-1)/2 = A112777(n)^2. MATHEMATICA Select[Range[111]^2, Plus @@ Last /@ FactorInteger[2# + 1] == 2 &] (* Ray Chandler, Nov 10 2005 *) Select[Range[120]^2, PrimeOmega[2#+1]==2&] (* Harvey P. Dale, Jul 22 2013 *) CROSSREFS Cf. A111351, A112777. Sequence in context: A075576 A295921 A338406 * A223221 A210002 A105078 Adjacent sequences:  A111347 A111348 A111349 * A111351 A111352 A111353 KEYWORD nonn AUTHOR Giovanni Teofilatto, Oct 29 2005 EXTENSIONS Edited and extended by Ray Chandler, Nov 10 2005 Offset corrected by Arkadiusz Wesolowski, Aug 09 2011 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 14 12:11 EDT 2021. Contains 342949 sequences. (Running on oeis4.)