



1, 4, 3, 12, 6, 30, 10, 50, 15, 60, 21, 84, 28, 140, 36, 180, 45, 180, 55, 220, 66, 330, 78, 390, 91, 364, 105, 420, 120, 600, 136, 680, 153, 612, 171, 684, 190, 950, 210, 1050, 231, 924, 253, 1012, 276, 1380, 300, 1500, 325, 1300, 351, 1404, 378, 1890, 406
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,2


REFERENCES

Norman Sullivan, Test Your Own IQ, Workman Publishing Co. New York, NY, 1994, pp. 48, 50.


LINKS

Harry J. Smith, Table of n, a(n) for n = 1..2000


MATHEMATICA

Array[{#, (4 + Boole[EvenQ@ #]) #} &@ PolygonalNumber@ # &, 28] // Flatten (* Michael De Vlieger, Jul 01 2018 *)


PROG

(PARI) { f="b061727.txt"; for (n=1, 1000, a=n*(n + 1)/2; if (a%2, t=a*4, t=a*5); write(f, 2*n  1, " ", a); write(f, 2*n, " ", t) ) } \\ Harry J. Smith, Jul 27 2009


CROSSREFS

Cf. A000217, A061726.
Sequence in context: A106285 A240134 A193800 * A327916 A270025 A271199
Adjacent sequences: A061724 A061725 A061726 * A061728 A061729 A061730


KEYWORD

nonn,dumb,easy


AUTHOR

Jason Earls, May 05 2001


EXTENSIONS

More terms from David Wasserman, Jun 25 2002


STATUS

approved



