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.

Previous Showing 41-48 of 48 results.

A180553 Primes that become a different prime under the mapping 5 <=> 8.

Original entry on oeis.org

53, 59, 83, 89, 151, 181, 251, 281, 353, 359, 383, 389, 457, 487, 509, 521, 523, 557, 563, 577, 587, 653, 683, 757, 787, 809, 821, 823, 857, 863, 877, 887, 953, 983, 1151, 1181, 1259, 1289, 1451, 1453, 1459, 1481, 1483, 1489, 1511, 1523, 1531, 1559, 1567
Offset: 1

Views

Author

Zak Seidov and Robert G. Wilson v, Sep 09 2010

Keywords

Links

Crossrefs

Cf. A171046, A175791, A180517 thru A180559, A175789, A180560, A180561.

Programs

  • Mathematica
    fQ[n_] := Block[{id = IntegerDigits@n}, (MemberQ[id, 5] || MemberQ[id, 8]) && PrimeQ[ FromDigits[ id /. {5 -> 8, 8 -> 5}] ]]; Select[ Prime@ Range@ 250, fQ]

A180554 Primes that become a different prime under the mapping 5 <=> 9.

Original entry on oeis.org

151, 157, 191, 197, 541, 547, 557, 571, 577, 593, 757, 797, 941, 947, 953, 971, 977, 997, 1051, 1091, 1153, 1193, 1453, 1493, 1531, 1553, 1657, 1697, 1931, 1993, 2503, 2593, 2857, 2897, 2903, 2953, 3511, 3517, 3547, 3911, 3917, 3947, 4051, 4091, 4357
Offset: 1

Views

Author

Zak Seidov and Robert G. Wilson v, Sep 09 2010

Keywords

Links

Crossrefs

Cf. A171054, A175791, A180517 thru A180559, A175789, A180560, A180561.

Programs

  • Mathematica
    fQ[n_] := Block[{id = IntegerDigits@n}, (MemberQ[id, 5] || MemberQ[id, 9]) && PrimeQ[ FromDigits[ id /. {5 -> 9, 9 -> 5}] ]]; Select[ Prime@ Range@ 600, fQ]

A180555 Primes that become a different prime under the mapping 6 <=> 7.

Original entry on oeis.org

61, 71, 163, 173, 601, 619, 643, 701, 719, 743, 1609, 1621, 1709, 1721, 1861, 1871, 2689, 2789, 3361, 3371, 3671, 3761, 4261, 4271, 4363, 4373, 4603, 4621, 4651, 4703, 4721, 4751, 4861, 4871, 5563, 5573, 5641, 5669, 5683, 5741, 5779, 5783, 5869, 5879
Offset: 1

Views

Author

Zak Seidov and Robert G. Wilson v, Sep 09 2010

Keywords

Links

Crossrefs

Cf. A171040, A175791, A180517 thru A180559, A175789, A180560, A180561.

Programs

  • Maple
    g:= proc(n) local L,i;
  L:= subs({6=7,7=6},convert(n,base,10));
  add(L[i]*10^(i-1),i=1..nops(L))
end proc:
filter:= proc(x) local y;
  if not isprime(x) then return false fi;
  y:= g(x);
  y <> x and isprime(y)
end proc:
select(filter, [seq(i,i=3..10000,2)]); # Robert Israel, Nov 12 2019
  • Mathematica
    fQ[n_] := Block[{id = IntegerDigits@n}, (MemberQ[id, 6] || MemberQ[id, 7]) && PrimeQ[ FromDigits[ id /. {6 -> 7, 7 -> 6}] ]]; Select[ Prime@ Range@ 780, fQ]

A180556 Primes that become a different prime under the mapping 6 <=> 8.

Original entry on oeis.org

263, 283, 467, 487, 653, 659, 661, 677, 683, 853, 859, 863, 877, 881, 1361, 1381, 1601, 1669, 1801, 1889, 2063, 2069, 2083, 2089, 2267, 2287, 2633, 2657, 2833, 2857, 3167, 3187, 3623, 3677, 3823, 3877, 4463, 4483, 4967, 4987, 5261, 5281, 5639, 5651, 5657
Offset: 1

Views

Author

Zak Seidov and Robert G. Wilson v, Sep 09 2010

Keywords

Links

Crossrefs

Cf. A171047, A175791, A180517 thru A180559, A175789, A180560, A180561.

Programs

  • Mathematica
    fQ[n_] := Block[{id = IntegerDigits@n}, (MemberQ[id, 6] || MemberQ[id, 8]) && PrimeQ[ FromDigits[ id /. {6 -> 8, 8 -> 6}] ]]; Select[ Prime@ Range@ 750, fQ]

A180557 Primes that become a different prime under the mapping 6 <=> 9.

Original entry on oeis.org

67, 97, 163, 167, 193, 197, 263, 293, 367, 397, 461, 491, 563, 593, 607, 641, 647, 653, 661, 677, 683, 907, 941, 947, 953, 977, 983, 991, 1061, 1063, 1091, 1093, 1163, 1193, 1567, 1597, 1601, 1607, 1613, 1663, 1667, 1901, 1907, 1913, 1993, 1997, 2267, 2297
Offset: 1

Views

Author

Zak Seidov and Robert G. Wilson v, Sep 09 2010

Keywords

Links

Crossrefs

Cf. A171055, A175791, A180517 thru A180559, A175789, A180560, A180561.

Programs

  • Mathematica
    fQ[n_] := Block[{id = IntegerDigits@n}, (MemberQ[id, 6] || MemberQ[id, 9]) && PrimeQ[ FromDigits[ id /. {6 -> 9, 9 -> 6}] ]]; Select[ Prime@ Range@ 350, fQ]

A180558 Primes that become a different prime under the mapping 7 <=> 8.

Original entry on oeis.org

73, 79, 83, 89, 271, 281, 373, 379, 383, 389, 673, 683, 709, 739, 773, 809, 839, 883, 1171, 1181, 1279, 1289, 1471, 1481, 1723, 1783, 1789, 1823, 1873, 1879, 2371, 2381, 2719, 2789, 2819, 2879, 3079, 3089, 3571, 3581, 3733, 3779, 3833, 3889, 4273, 4283
Offset: 1

Views

Author

Zak Seidov and Robert G. Wilson v, Sep 09 2010

Keywords

Links

Crossrefs

Cf. A171048, A175791, A180517 thru A180559, A175789, A180560, A180561.

Programs

  • Mathematica
    fQ[n_] := Block[{id = IntegerDigits@n}, (MemberQ[id, 7] || MemberQ[id, 8]) && PrimeQ[ FromDigits[ id /. {7 -> 8, 8 -> 7}] ]]; Select[ Prime@ Range@ 600, fQ]

A180581 Least prime p which maps into n different primes under some mapping of a single decimal digit <=> with another single decimal digit.

Original entry on oeis.org

11, 1187, 449, 2, 61, 29, 19, 23, 17, 13, 109, 1021, 107, 10427, 78041, 10457, 190583, 1309757, 2531689, 152944307
Offset: 0

Views

Author

Robert G. Wilson v, Sep 10 2010

Keywords

Comments

a(n) > 10^9 for n >= 20. [From Donovan Johnson, Oct 05 2010]

Links

  • Index to Primes, Primes that become a different prime under some mapping.

Crossrefs

Cf. A171057, A175791, A180517 thru A180559, A175789, A180560, A180561.

Programs

  • Mathematica
    fQ[n_] := Block[{id = IntegerDigits@n}, (MemberQ[id, s[[1]]] || MemberQ[id, s[[2]]]) && PrimeQ[FromDigits[id /. {s[[1]] -> s[[2]], s[[2]] -> s[[1]]}]]]; f[n_] := Count[ Flatten[ Table[s = {j, k}; fQ@n, {j, 0, 8}, {k, j + 1, 9}]], True]; t = Table[0, {46}]; p = 2; While[p < 13500000, a = f@p; If[ t[[a + 1]] == 0, t[[a + 1]] = p; Print[{a, p}]]; p = NextPrime@p]; t

Extensions

a(19) from Donovan Johnson, Oct 05 2010

A232422 Integers n such that n^2 becomes another square under the map 8<=>9 (acting on the decimal digits).

Original entry on oeis.org

621, 629, 6210, 6290, 43415, 44665, 62100, 62900, 113405, 113845, 434150, 446650, 621000, 629000, 677131, 677869, 918545, 971455, 1134050, 1138450, 1260718, 1264282, 1355425, 1391825, 3373885, 3375365, 3854525, 3867475, 4341500, 4466500, 6210000, 6290000, 6771310, 6778690, 9185450, 9714550
Offset: 1

Views

Author

Zak Seidov, Nov 23 2013

Keywords

Comments

If n is a term then 10n is also a term.
n^2 must contain an 8, a 9, or both. - Harvey P. Dale, Jun 17 2022

Examples

			621^2=385641 <=> 395641 = 629^2, so both 621 and 629 are terms.
43415=1884862225 <=>1994962225=44665^2, so both 43415 and 44665 are terms.

Crossrefs

A175789 (primes with similar property).

Programs

  • Mathematica
    fQ[n_]:=Block[{id=IntegerDigits@n^2},(MemberQ[id,8]||MemberQ[id,9])&&
        IntegerQ[Sqrt[FromDigits[id/.{8->9,9->8}]]]]; Reap[Do[If[fQ[n],Sow[n]],{n,10000000}]][[2,1]]
Select[Range[10^7],Max[IntegerDigits[#^2]]>7&&IntegerQ[Sqrt[ FromDigits[ IntegerDigits[ #^2]/.{8->9,9->8}]]]&]  (* Harvey P. Dale, Jun 17 2022 *)
Previous Showing 41-48 of 48 results.

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