A343035 a(n) = A343033(n, n).

1, 2, 5, 4, 11, 30, 17, 8, 25, 110, 23, 60, 31, 238, 385, 16, 41, 150, 47, 220, 935, 506, 59, 120, 121, 806, 125, 476, 67, 2310, 73, 32, 1495, 1394, 2431, 900, 83, 1786, 2635, 440, 97, 39270, 103, 1012, 1925, 2714, 109, 240, 289, 1210, 3895, 1612, 127, 750

Offset

1,2

Comments

This sequence has similarities with A087019.

Links

Rémy Sigrist, Table of n, a(n) for n = 1..10000

Index entries for sequences related to dismal (or lunar) arithmetic

Formula

a(n) = n iff n is a power of 2 (A000079).

a(prime(i)^k) = prime(2*i-1)^k for any i > 0 and k > 0.

Example

For n = 40:
- 40 = 5 * 2^3, so:
          (11 7 5 3 2)
                1 0 3
              x 1 0 3
              -------
                1 0 3
              0 0 0
          + 1 0 1
          -----------
            1 0 1 0 3,
- hence a(40) = 11 * 5 * 2^3 = 440.

Prog

(PARI) a(n) = { my (r=1, pp=factor(n)[, 1]~); for (i=1, #pp, for (j=1, #pp, my (p=prime(primepi(pp[i])+primepi(pp[j])-1), v=valuation(r, p), w=min(valuation(n, pp[i]), valuation(n, pp[j]))); if (w>v, r*=p^(w-v)))); r }

Crossrefs

Cf. A000079, A087019, A343033.

Sequence in context: A319525 A357983 A338459 * A002314 A177979 A362707

Adjacent sequences: A343032 A343033 A343034 * A343036 A343037 A343038

Keyword

nonn

Author

Rémy Sigrist, Apr 03 2021

Status

approved