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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; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..32.

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: A051205 A168114 A220656 * A266986 A047283 A155932

Adjacent sequences:  A050241 A050242 A050243 * A050245 A050246 A050247

KEYWORD

more,nonn

AUTHOR

Hugo Pfoertner, May 08 2003

EXTENSIONS

Corrected and extended by Hugo Pfoertner, May 12 2003

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

5 more terms from Sean A. Irvine, Nov 05 2009

STATUS

approved

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Last modified May 27 11:51 EDT 2017. Contains 287205 sequences.