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- #!/usr/bin/ruby
- # a(n)-th prime is the smallest prime containing exactly n 0's.
- # https://oeis.org/A037052
- var h = Hash(
- 0 2
- 1 101
- 2 1009
- 3 10007
- 4 100003
- 5 1000003
- 6 20000003
- 7 100000007
- 8 1000000007
- 9 30000000001
- 10 100000000003
- 11 2000000000003
- 12 40000000000001
- 13 1000000000000037
- 14 6000000000000001
- 15 20000000000000003
- 16 100000000000000003
- 17 1000000000000000003
- 18 60000000000000000007
- 19 500000000000000000003
- 20 8000000000000000000009
- 21 10000000000000000000009
- 22 1000000000000000000000049
- 23 1000000000000000000000007
- )
- for v in (h.values.sort) {
- if (v.to_s =~ /^1/) {
- say [v, primepi(10**v.ilog10) + primepi(10**v.ilog10, v)]
- }
- else {
- say [v, primepi(v)]
- }
- }
- __END__
- [2, 1]
- [101, 26]
- [1009, 169]
- [10007, 1230]
- [100003, 9593]
- [1000003, 78499]
- [20000003, 1270608]
- [100000007, 5761456]
- [1000000007, 50847535]
- [30000000001, 1300005927]
- [100000000003, 4118054814]
- [2000000000003, 73301896140]
- [40000000000001, 1320811971703]
- [1000000000000037, 29844570422670]
- [6000000000000001, 169969662554552]
- [20000000000000003, 547863431950009]
- [100000000000000003, 2623557157654234]
- [1000000000000000003, 24739954287740861]
- 1, 26, 169, 1230, 9593, 78499, 1270608, 5761456, 50847535, 1300005927, 4118054814, 73301896140, 1320811971703, 29844570422670, 169969662554552, 547863431950009, 2623557157654234, 24739954287740861
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