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A106390
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Numbers k such that 13k = 6j^2 + 6j + 1.
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3
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1, 61, 97, 277, 349, 649, 757, 1177, 1321, 1861, 2041, 2701, 2917, 3697, 3949, 4849, 5137, 6157, 6481, 7621, 7981, 9241, 9637, 11017, 11449, 12949, 13417, 15037, 15541, 17281, 17821, 19681, 20257, 22237, 22849, 24949, 25597, 27817, 28501, 30841
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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LINKS
| Index to sequences with linear recurrences with constant coefficients, signature (1,2,-2,-1,1).
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FORMULA
| k(1)=1, k(2)=61; then if n odd k(n)=k(n-1)+18*(n-1), if n even k(n)=k(n-1)+60*(n-1)
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MATHEMATICA
| f[n_] := Block[{k = (6n(n + 1) + 1)/13}, If[ IntegerQ[k], k, 1]]; Union[ Table[ f[n], {n, 270}]] (from Robert G. Wilson v (rgwv(AT)rgwv.com), May 02 2005)
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CROSSREFS
| Cf. A106387, A106388, A106389.
For j sequence see A106389.
Sequence in context: A020350 A142108 A033239 * A142191 A086126 A023287
Adjacent sequences: A106387 A106388 A106389 * A106391 A106392 A106393
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KEYWORD
| nonn,easy
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AUTHOR
| Pierre CAMI (pierre-cami(AT)bbox.fr), May 01 2005
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EXTENSIONS
| More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), May 02 2005
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