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A050244 Numbers n such that 2^n + 3^n is a semiprime. 1
3, 6, 7, 8, 10, 11, 12, 14, 16, 22, 32, 34, 38, 82, 83, 106, 128, 149, 218, 223, 334, 412, 436, 599, 647, 916, 1373, 4414, 7246, 8423, 10118, 10942 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

EXAMPLE

a(1)=3 because 2^3+3^3 = 5 * 7

a(2)=6 because 2^6+3^6 = 13 * 61

a(3)=7 because 2^7+3^7 = 5 * 463

a(4)=8 because 2^8+3^8 = 17 * 401

a(5)=10 because 2^10+3^10 = 13 * 4621

a(6)=11 because 2^11+3^11 = 5 * 35839

a(7)=12 because 2^12+3^12 = 97 * 5521

a(8)=14 because 2^14+3^14 = 13 * 369181

a(9)=16 because 2^16+3^16 = 3041 * 14177

a(10)=22 because 2^22+3^22 = 13 * 2414250301

a(11)=32 because 2^32+3^32 = 1153 * 1607133116929

a(12)=34 because 2^34+3^34 = 13 * 1282861452271981

a(13)=38 because 2^38+3^38 = 13 * 103911691734684541

a(14)=82 because 2^82+3^82 = 13 * 102329189594547549657540565413396038701

a(15)=83 because 2^83+3^83 = 5 * 798167678837469920188160718521149336927

a(16)=106 because 2^106+3^106 = 13 * 28900785585664327723593061693364968422740414514061

a(17)=128 because 2^128+3^128 = 257 * 45876204582640401445607833244277975113391731388650867226881

a(18)=149 because 2^149+3^149 = 5 * 24665899002341798194980052306171212216360861465143461865961807325057879

CROSSREFS

Cf. A001358, A082101.

Sequence in context: A189822 A051205 A168114 * A047283 A155932 A047557

Adjacent sequences:  A050241 A050242 A050243 * A050245 A050246 A050247

KEYWORD

more,nonn

AUTHOR

Hugo Pfoertner (hugo(AT)pfoertner.org), May 08 2003

EXTENSIONS

Corrected and extended by Hugo Pfoertner (hugo(AT)pfoertner.org), May 12 2003

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Dec 30 2007

5 more terms from Sean A. Irvine (sairvin(AT)xtra.co.nz), Nov 05 2009

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Last modified February 14 14:47 EST 2012. Contains 205623 sequences.