A234850 -id:A234850 - cp's OEIS frontend

A234851 Indices of primes in A014692, i.e., numbers k such that prime(k)-k+1 is prime.

1, 2, 3, 5, 7, 13, 17, 21, 23, 25, 31, 41, 43, 49, 61, 71, 77, 83, 89, 103, 105, 109, 121, 129, 133, 139, 151, 161, 173, 181, 183, 185, 189, 199, 211, 213, 223, 231, 235, 241, 243, 247, 265, 271, 273, 277, 279, 281, 285, 293, 301, 303, 307, 311, 317

Offset: 1

M. F. Hasler, Dec 31 2013

nonn

Sequence A234695 lists primes in this sequence.

Robert Israel, Table of n, a(n) for n = 1..10000

Cf. A000040, A000720, A014692, A234695, A234850, A234852.

select(k -> isprime(ithprime(k)-k+1), [$1..1000]); # Robert Israel, Feb 19 2021

for(k=1,999,isprime(prime(k)-k+1)&&print1(k","))

PARI
```
is_A234851(n)=isprime(prime(k)-k+1)
```

a(n) = PrimePi(A234850(n)), PrimePi = A000720.

A234852 Indices k of primes p=prime(k) such that prime(p)-p+1 is prime.

Original entry on oeis.org

1, 2, 3, 4, 6, 7, 9, 11, 13, 14, 18, 20, 23, 24, 27, 29, 34, 36, 40, 42, 46, 47, 48, 53, 58, 59, 60, 62, 63, 64, 66, 68, 70, 71, 73, 90, 95, 100, 103, 105, 110, 121, 122, 127, 128, 132, 133, 134, 141, 143, 144, 153, 155, 156, 162

Offset: 1

M. F. Hasler, Dec 31 2013

nonn

Cf. A000040, A000720, A014692, A234850, A234851.

Select[Range[200],PrimeQ[Prime[Prime[#]]-Prime[#]+1]&] (* Harvey P. Dale, Jul 14 2024 *)

for(k=1,999,isprime(prime(p=prime(k))-p+1)&&print1(k","))

a(n) = PrimePi(A234695(n)), PrimePi = A000720.

A234853 Indices of primes in A234851.

Original entry on oeis.org

2, 3, 4, 5, 6, 7, 9, 11, 12, 13, 15, 16, 18, 19, 20, 22, 26, 27, 29, 30, 34, 35, 37, 40, 44, 46, 48, 50, 53, 54, 55, 59, 60, 61, 62, 68, 76, 79, 80, 81, 85, 89, 91, 94, 96, 99, 100, 102, 110, 111, 112, 117, 122, 123, 125, 126, 134, 138, 139, 141, 144, 147

Offset: 1

M. F. Hasler, Dec 31 2013

nonn

Cf. A000040, A000720, A014692, A234850, A234851, A234852, A234695.

c=0;for(k=1,1999,isprime(prime(k)-k+1)&&c++&&isprime(k)&&print1(c", "))

cp's OEIS Frontend

A234851 Indices of primes in A014692, i.e., numbers k such that prime(k)-k+1 is prime.

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A234852 Indices k of primes p=prime(k) such that prime(p)-p+1 is prime.

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PARI

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A234853 Indices of primes in A234851.

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PARI