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 1-2 of 2 results.

A259032 Numbers n such that digital root of n is 2*(digital root of n-th prime).

Original entry on oeis.org

29, 38, 40, 44, 49, 80, 143, 148, 166, 191, 197, 233, 251, 269, 272, 283, 305, 314, 326, 335, 364, 371, 373, 389, 425, 427, 431, 461, 470, 497, 515, 517, 553, 557, 562, 602, 614, 616, 625, 634, 638, 647, 652, 656, 659, 661, 677, 683, 692, 731, 749, 758, 800, 812, 845, 863, 908
Offset: 1

Views

Author

Zak Seidov, Jun 17 2015

Keywords

Comments

Corresponding primes:
109, 163, 173, 193, 227, 409, 823, 857, 983, 1153, 1201, 1471, 1597, 1723, 1747, 1847, 2011, 2083, 2161, 2251, 2459, 2539, 2549, 2683, 2953, 2963, 3001, 3259, 3331, 3547, 3691, 3701, 4007, 4027, 4079, 4423, 4519, 4547, 4637, 4691, 4729, 4801, 4871, 4909, 4933, 4943, 5059, 5107, 5197.
Conjecture: a(n) ~ 18n. - Charles R Greathouse IV, Jun 18 2015

Crossrefs

Cf. A010888, A038194, A258876, A258877, A259040.

Programs

  • Mathematica
    Reap[Do[If[FixedPoint[Total[IntegerDigits[#]]&,n]==2*Mod[Prime[n],9],Sow[n]], {n,1000}]][[2,1]]
Select[Range@ 1000, FixedPoint[Total@ IntegerDigits@ # &, #] == 2 FixedPoint[Total@ IntegerDigits@ # &, Prime@ #] &] (* Michael De Vlieger, Jun 19 2015 *)
  • PARI
    n=0;forprime(p=2,1e4, if(p%9*2==n++%9, print1(n", "))) \\ Charles R Greathouse IV, Jun 18 2015

A259041 Numbers n such that digital root of n is 4*(digital root of n-th prime).

Original entry on oeis.org

26, 31, 58, 71, 89, 107, 112, 116, 157, 161, 193, 211, 247, 310, 337, 395, 458, 490, 503, 535, 580, 584, 620, 688, 769, 778, 841, 850, 859, 868, 872, 877, 895, 949, 985, 989, 1034, 1070, 1079, 1102, 1106, 1133, 1138, 1142, 1192, 1201, 1210, 1214, 1219, 1232, 1255, 1277, 1282, 1295, 1300, 1327, 1412, 1493, 1511, 1538
Offset: 1

Views

Author

Zak Seidov, Jun 17 2015

Keywords

Comments

Corresponding primes:
101, 127, 271, 353, 461, 587, 613, 641, 919, 947, 1171, 1297, 1567, 2053, 2269, 2711, 3251, 3511, 3593, 3853, 4231, 4259, 4583, 5167, 5851, 5923, 6481, 6571, 6661, 6733, 6779, 6823, 6967, 7489, 7759, 7823, 8237, 8597, 8669, 8839, 8867, 9137, 9181, 9209, 9649, 9739, 9811, 9839, 9883.
Conjecture: a(n) ~ 27n. - Charles R Greathouse IV, Jun 18 2015

Crossrefs

Cf. A010888, A038194, A258876, A258877, A259032, A259040.

Programs

  • Mathematica
    Reap[Do[If[FixedPoint[Total[IntegerDigits[#]]&,n]==4*Mod[Prime[n],9], Sow[{n,Prime[n]}]],{n,2000}]][[2,1]]
  • PARI
    n=0; forprime(p=2, 1e4, if(p%9*4==n++%9, print1(n", "))) \\ Charles R Greathouse IV, Jun 18 2015
Showing 1-2 of 2 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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