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A095894 a(2n) = 6n^2+7n+1; a(2n+1) = 6n^2+13n+7. 1
1, 7, 14, 26, 39, 57, 76, 100, 125, 155, 186, 222, 259, 301, 344, 392, 441, 495, 550, 610, 671, 737, 804, 876, 949, 1027, 1106, 1190, 1275, 1365, 1456, 1552, 1649, 1751, 1854, 1962, 2071, 2185, 2300, 2420, 2541, 2667, 2794, 2926, 3059, 3197, 3336, 3480 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Positives A051866 and positives A049453 interleaved. Also sequence found by reading the line from 1, in the direction 1, 14... and the line from 7, in the direction 7, 26,..., in the square spiral whose vertices are the generalized pentagonal numbers A001318. - Omar E. Pol, Jul 18 2012

LINKS

Table of n, a(n) for n=0..47.

Index entries for linear recurrences with constant coefficients, signature (2,0,-2,1).

FORMULA

G.f. ( -1-5*x ) / ( (1+x)*(x-1)^3 ). - R. J. Mathar, Oct 26 2011

MATHEMATICA

LinearRecurrence[{2, 0, -2, 1}, {1, 7, 14, 26}, 60] (* Harvey P. Dale, Oct 13 2016 *)

CROSSREFS

Cf. A047225 (first differences).

Sequence in context: A232871 A232854 A232790 * A104599 A115874 A083495

Adjacent sequences:  A095891 A095892 A095893 * A095895 A095896 A095897

KEYWORD

nonn,easy

AUTHOR

Gary W. Adamson, Jun 11 2004

EXTENSIONS

Edited by Don Reble (djr(AT)nk.ca), Nov 16 2005

STATUS

approved

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Last modified December 9 16:22 EST 2016. Contains 278985 sequences.