A077128 Smallest number greater than the previous term which is relatively prime to each of the group of the next n numbers.
2, 5, 7, 11, 17, 23, 29, 37, 47, 59, 67, 79, 97, 107, 127, 137, 157, 173, 191, 211, 233, 257, 277, 307, 331, 353, 379, 409, 439, 467, 499, 541, 563, 599, 631, 673, 709, 743, 787, 821, 863, 907, 947, 991, 1039, 1087, 1129, 1181, 1229, 1277, 1327, 1381, 1433
Offset: 1
Keywords
Examples
a(6) = 23 is the smallest number coprime to 16,17,18,19,20 and 21. - _R. J. Mathar_, Sep 02 2008
Crossrefs
Cf. A097050. - R. J. Mathar, Sep 02 2008
Programs
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Maple
A000217 := proc(n) n*(n+1)/2 ; end: A077128 := proc(n) option remember ; local ts,a,goodk,k ; if n = 1 then RETURN(2) ; fi; ts := [seq(A000217(n-1)+i,i=1..n)] ; for a from procname(n-1)+1 do goodk := true ; for k in ts do if gcd(a,k) <> 1 then goodk := false; break ; fi; od: if goodk then RETURN(a) ; fi; od: end: for n from 1 to 100 do printf("%d,",A077128(n)) ; od: # R. J. Mathar, Sep 02 2008
Extensions
Extended beyond a(10) by R. J. Mathar, Sep 02 2008
Comments