cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-4 of 4 results.

A229203 Primes of the form k^3 - prime(k).

Original entry on oeis.org

5, 971, 54709, 73907, 84991, 124771, 287179, 404851, 511591, 728537, 4095059, 5638691, 6433747, 6857849, 10646627, 11238001, 11850913, 12811423, 13479779, 13822489, 14170957, 16775597, 17574343, 19681267, 20121901, 21950189, 26461619, 39999391, 49025423, 49833529
Offset: 1

Views

Author

K. D. Bajpai, Sep 15 2013

Keywords

Examples

			a(2)=971: 10^3-prime(10)= 1000-29= 971 which is prime.
		

Crossrefs

Programs

  • Maple
    KD:= proc() local a; a:= k^3-ithprime(k); if isprime(a) then RETURN(a): fi; end: seq(KD(),k=1..1000);
  • Mathematica
    Select[Table[k^3-Prime[k],{k,1000}],PrimeQ]
  • PARI
    for(k=1, 10^3, if(ispseudoprime(KD=eval((k^3-prime(k)))), print1(KD", ")));

A212304 Primes of the form prime(n)^2 + n.

Original entry on oeis.org

5, 11, 53, 1381, 3739, 6263, 12799, 32803, 57173, 177323, 187573, 491527, 674183, 1067263, 1125899, 1142941, 1230067, 1352761, 1471567, 1745257, 1885349, 2283361, 2563453, 2779151, 3893027, 4364237, 5508757, 6933071, 7513481, 7790087, 8048981, 9370159, 11499359
Offset: 1

Views

Author

K. D. Bajpai, Oct 24 2013

Keywords

Examples

			a(3) = 53 :  prime(4)^2 + 4 = 7^2 + 4 = 49 + 4 = 53 which is prime.
a(4) = 1381 :  prime(12)^2 + 12 = 37^2 + 12 = 1369 + 12 = 1381 which is prime.
		

Crossrefs

Cf. A000040 (prime numbers).
Cf. A184935 (primes: k^2 + prime(k)).
Cf. A188831 (primes: k^2 - prime(k)).
Cf. A229203 (primes: k^3 - prime(k)).

Programs

  • Maple
    with(numtheory):KD := proc() local a; a:= (ithprime(k)^2+k); if isprime(a) then RETURN (a); fi; end: seq(KD(),k=1..1000);
  • Mathematica
    Select[Table[Prime[k]^2 + k, {k, 1000}], PrimeQ]
  • PARI
    for(k=1, 10^5, if(ispseudoprime(KD=((prime(k)^2+k))), print1(KD", ")));

A227890 Primes of the form prime(k)^2 - k.

Original entry on oeis.org

3, 7, 163, 353, 5021, 12739, 32719, 49681, 52391, 78901, 113501, 252913, 361091, 452807, 551917, 993841, 1559797, 1956979, 2193127, 3463037, 4067983, 5003837, 5138953, 6115363, 6723271, 7251857, 7447043, 7578607, 8426989, 9479801, 11295847, 12186593, 12439237
Offset: 1

Views

Author

K. D. Bajpai, Oct 26 2013

Keywords

Examples

			a(3)= 163: prime(6)^2 - 6= 13^2 - 6= 169 - 6= 163 which is prime.
a(4)= 353: prime(8)^2 - 8= 19^2 - 8= 361 - 8= 353 which is prime.
		

Crossrefs

Cf. A000040 (prime numbers).
Cf. A064713 (for the integers k).
Cf. A184935 (primes: k^2 + prime(k)).
Cf. A188831 (primes: k^2 - prime(k)).
Cf. A229203 (primes: k^3 - prime(k)).

Programs

  • Maple
    with(numtheory):KD := proc() local a; a:= (ithprime(k)^2-k); if isprime(a) then RETURN (a); fi; end: seq(KD(), k=1..1000);
  • Mathematica
    Select[Table[Prime[k]^2-k,{k,1000}],PrimeQ]
  • PARI
    for(k=1, 10^5, if(ispseudoprime(KD=((prime(k)^2-k))), print1(KD", ")));

A239743 Primes of the form prime(k)^3 + k.

Original entry on oeis.org

29, 347, 2203, 704993, 2248123, 2685653, 3442987, 81182821, 86938393, 95444081, 230346509, 1064332433, 1298596753, 1829276767, 2202074113, 3449796071, 4306879141, 6740558659, 8205739219, 9649993009, 11650768499, 14225261327, 15124198183, 19968681493, 21415471837
Offset: 1

Views

Author

K. D. Bajpai, Mar 26 2014

Keywords

Examples

			29 is in the sequence because prime(2)^3 + 2 = 29, which is prime.
347 is in the sequence because prime(4)^3 + 4 = 347, which is prime.
		

Crossrefs

Cf. A000040 (prime numbers).
Cf. A184935 (primes: k^2 + prime(k)).
Cf. A188831 (primes: k^2 - prime(k)).
Cf. A229203 (primes: k^3 - prime(k)).
Cf. A061068 (primes: prime(k) + k)
Cf. A212304 (primes: prime(k)^2 + k).

Programs

  • Magma
    [q: k in [1..1000] | IsPrime(q) where q is NthPrime(k)^3+k]; // Bruno Berselli, Mar 26 2014
  • Maple
    KD := proc() local a,b; a:= ithprime(n); b:=a^3+n; if isprime(b) then RETURN (b); fi; end: seq(KD(), n=1..1000);
  • Mathematica
    Select[Table[Prime[k]^3 + k, {k, 1000}], PrimeQ]
  • PARI
    s=[]; for(k=1, 1000, n=prime(k)^3+k; if(isprime(n), s=concat(s, n))); s \\ Colin Barker, Mar 26 2014
    
Showing 1-4 of 4 results.