Smarandache-Wellin primes: Difference between revisions

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// Smarandache-Wellin primes. Nigel Galloway: April 3rd., 2023

let izP(g,_,_,_)=let mutable g=System.Numerics.BigInteger.Parse g

Open.Numeric.Primes.MillerRabin.IsProbablePrime &g

let fN g="0123456789"+g|>Seq.countBy id|>Seq.map(fun(_,g)->string(g-1))|>Seq.fold((+))""

let sw()=primes32()|>Seq.scan(fun(n,i,g,e)l->let a=string l in (n+a,l,g+1,e+(String.length a)))("",0,0,0)|>Seq.skip 1

sw()|>Seq.filter izP|>Seq.take 3|>Seq.iter(fun(i,_,_,_)->printf "%s " i); printfn ""

sw()|>Seq.filter izP|>Seq.take 7|>Seq.iter(fun(_,n,g,l)->printfn "index %4d: digits %4d last prime %d" g l n); printfn ""

sw()|>Seq.map(fun(i,g,e,l)->(fN i,g,e,l))|>Seq.filter izP|>Seq.take 20|>Seq.iter(fun(n,_,g,_)->printfn $"index %4d{g}: prime %s{n}")

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<pre>

2 23 2357

index 1: digits 1 last prime 2

index 2: digits 2 last prime 3

index 4: digits 4 last prime 7

index 128: digits 355 last prime 719

index 174: digits 499 last prime 1033

index 342: digits 1171 last prime 2297

index 435: digits 1543 last prime 3037

index 32: prime 4194123321127

index 72: prime 547233879626521

index 73: prime 547233979727521

index 134: prime 13672766322929571043

index 225: prime 3916856106393739943689

index 303: prime 462696313560586013558131

index 309: prime 532727113760586013758133

index 363: prime 6430314317473636515467149

index 462: prime 8734722823685889120488197

index 490: prime 9035923128899919621189209

index 495: prime 9036023329699969621389211

index 522: prime 9337023533410210710923191219

index 538: prime 94374237357103109113243102223

index 624: prime 117416265406198131121272110263

index 721: prime 141459282456260193137317129313

index 738: prime 144466284461264224139325131317

index 790: prime 156483290479273277162351153339

index 852: prime 164518312512286294233375158359

index 1087: prime 208614364610327343341589284471

index 1188: prime 229667386663354357356628334581

</pre>