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Search: id:A050244
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A050244 Numbers n such that 2^n + 3^n is a semiprime. +0
2
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 (list; graph; listen)
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.

Adjacent sequences: A050241 A050242 A050243 this_sequence A050245 A050246 A050247

Sequence in context: A113826 A053030 A051205 this_sequence A047283 A047557 A099850

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

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Last modified October 15 09:18 EDT 2008. Contains 145015 sequences.


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