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Sosa-Stradonitz numbering
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In genealogy , for numbering ancestors of some person is used
Sosa Stradonitz numbering
(in abbreviated form Sosa numbering).

In that numbering the number 1 is allocated to the family tree root of the genealogya person named "de cujus"
To her father the number 2 ,is allocated ,to her mother number 3 and to her four grandparents numbers 4, 5, 6 and 7
As a rule, if a person of the ancestry has N as number Sosa :
  her father has 2 x N for Sosa number and her mother has 2 x N+1
  For every man , his Sosa number N is even (except for the "de cujus") and his spouse has N+1 for Sosa number and it is odd. For every woman her Sosa number N is odd and his husband has N-1 for Sosa number
  His or her son or daughter has integer(N / 2) for Sosa number
  Ancestors of g generation have Sosa numbers from 2g to 2g+1-1 and that generation includes 2g ancestors.

Nr generationBirthdayrelationship Sosa numbers
  1970/1980de cujus1
I1940/1950parents2, 3
II1910/1920grandparents4, 5, 6 ,7
III1880/1890great-grandparents8, 9, 10, 11, 12, 13, 14, 15
IV1850/1860ancestors 5th generationfrom 32 to 63
VI1790/1800ancestors 6th generationfrom 64 to 127
VI1760/1770ancestors 7th generationfrom 128 to 255
VII1730/1740ancestors 8th generationfrom 256 to 511
VIII1700/1710ancestors 9th generation from 512 to 1023
IX1670/1680ancestors 10th generationfrom 1024 to 2047
aa aa aa aa
XIX1370/1380ancestors 19th generationfrom 524.288 to 1.048.575
aa aa aa aa
XXXVII740/750
(Charlemagne)
ancestors 37th generation from 1,4 x 10 11 to 2,8 x 1011i.e 140 billion ancestors

An ancestor may have several Sosa numbers (if he is implexe).
It has to be said that Sosa numbering is used only for direct ancestors of the person studied.

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