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A123048 Semiprimes that are the sum of a positive square and a positive cube. 2
9, 10, 26, 33, 57, 65, 82, 91, 122, 129, 134, 141, 145, 161, 177, 185, 206, 217, 226, 265, 289, 321, 362, 381, 407, 427, 485, 505, 511, 537, 566, 626, 633, 667, 681, 689, 703, 737, 745, 778, 785, 793, 841, 842, 849, 898, 901, 905, 985, 1018, 1041, 1057, 1081 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Semiprime analog of A066649, Primes of the form a^2 + b^3 with a, b > 0.

LINKS

Giovanni Resta, Table of n, a(n) for n = 1..10000

FORMULA

A001358 INTERSECTION A055394.

EXAMPLE

a(1) = 9 = 2^3 + 1^2 = 3*3.

a(2) = 10 = 3^2 + 1^3 = 2*5.

a(3) = 26 = 5^2 + 1^3 = 2*13.

a(4) = 33 = 5^2 + 2^3 = 3*11.

a(5) = 57 = 7^2 + 2^3 = 3*19.

a(6) = 65 = 1^2 + 4^3 = 8^2 + 1^3 = 5*13.

MATHEMATICA

Select[ Union[ Plus @@@ Tuples[{Range[4^3]^2, Range[4^2]^3}]], # < 1082 && Plus @@ Last /@ FactorInteger[#] == 2 &] (* Giovanni Resta, Jun 12 2016 *)

CROSSREFS

Cf. A001358, A055394, A066649.

Sequence in context: A025043 A320728 A111033 * A189047 A041170 A041168

Adjacent sequences:  A123045 A123046 A123047 * A123049 A123050 A123051

KEYWORD

easy,nonn

AUTHOR

Jonathan Vos Post, Sep 25 2006

EXTENSIONS

More terms from Robert G. Wilson v, Sep 29 2006

STATUS

approved

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Last modified June 16 21:13 EDT 2019. Contains 324155 sequences. (Running on oeis4.)