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A108655 Primes that are sums of the squares of two semiprimes. 1
97, 181, 241, 277, 421, 457, 541, 641, 661, 709, 757, 821, 1109, 1117, 1237, 1301, 1381, 1597, 1621, 1669, 1709, 1901, 2069, 2341, 2381, 2417, 2437, 2557, 2617, 2677, 2741, 2797, 3041, 3061, 3221, 3557, 3637, 3701, 3733, 3989, 4241, 4261, 4421, 4517 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Subsequence of A002144.

a(n) = A074985(i) + A074985(j) for appropriate i and j.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

EXAMPLE

A000040(733) = 5557 = 81 + 5476 = (3*3)^2 + (2*37)^2 =

A001358(3)^2 + A001358(25)^2 = A074985(3) + A074985(25),

therefore 5557 is a term.

PROG

(Haskell)

a108655 n = a108655_list !! (n-1)

a108655_list = filter f a000040_list where

   f p = any (> 0) $ map (a064911 . a037213 . (p -)) $

                         takeWhile (< p) a074985_list

-- Reinhard Zumkeller, Aug 09 2012

CROSSREFS

Cf. A000404, A001358, A000290.

Sequence in context: A261376 A142094 A142212 * A107193 A256775 A142398

Adjacent sequences:  A108652 A108653 A108654 * A108656 A108657 A108658

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Jul 07 2005

STATUS

approved

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Last modified May 27 11:14 EDT 2017. Contains 287204 sequences.