The file icosahedral-forms.txt was submitted to me by Arnaud Jehanne (University Bordeaux I) March 2007. This file contains 27 icosahedral forms of weight 1 and real nebentyp which are, to my best knowledge state of June 2008, not covered by the known theorem concerning which 2-dimensional odd Galois representations are modular. The format of the file icosahedral forms is as follows: [space, space, ...] space: [ weight, level, character, form, form, ..., form, 512] weight: always equal to $1$. level: the $l$ such that the form is a new form for $\Gamma_0(l)$. character: the negative discriminant $D$ such that the Kronecker symbol $\big(\frac D*\big)$ is the nebentyp of the forms in this space. form: [ name, matrix, [pol_5, pol_24], coefficients] name: the forms in a given space are called "a", "b", .... matrix: ??? pol_5: polynomial defining the fixed field of the kernel of the corresponding projective Galois representation given as list of the coefficients in ascending order. pol_24: polynomial defining the fixed field of the kernel of the corresponding (proper) Galois representation given as list of the coefficients in ascending order. coefficients: 5000 x 5 matrix $M$ , such that the vector $M*(1, S, i, iS)^t$ contains the first 5000 Fourier coefficients of the form in question. Here $S=(-1+sqrt(5))/2$ and $i = \sqrt{-1}$. The number 512 is meaningless (it used to be magic number for a PARI/GP program). The levels and characters of the 18 spaces containing these 27 forms are as follows: No. level char. n. of forms ----------------------------------- 1 1948 -487 1 2 2083 -2083 1 3 2336 -292 2 4 2707 -2707 1 5 2863 -2863 2 6 3004 -751 1 7 3203 -3203 1 8 3547 -3547 1 9 3548 -887 1 10 3587 -3587 2 11 3676 -919 1 12 3775 -151 2 13 3775 -755 2 14 3875 -31 2 15 3875 -155 2 16 4000 -4 2 17 4000 -20 2 18 4027 -4027 1 Copyright (C) 2007 Arnaud Jehanne (Universit\'e Bordeaux I) Nils Skoruppa (University of Siegen)